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Working Paper Series

Stored Value Cards: Costly Private
Substitutes for Government Currency

WP 96-03

This paper can be downloaded without charge from:
http://www.richmondfed.org/publications/

Jeffrey M. Lacker
Federal Reserve Bank of Richmond

Working Paper 96-3

Stored Value Cards:
Costly Private Substitutes for Government Currency
Jeffrey M. Lacker*

Research Department
Federal Reserve Bank of Richmond**
April 29, 1996

Abstract: A model in which both currency and stored value cards are used to make payments is
presented. I compare steady-state equilibria with and without stored value cards. Stored value cards
are beneficial because they help alleviate the deadweight loss due to inflation. When the nominal
interest rate is greater than the government’s resource cost of providing currency, the alternative
means of payment may have larger real resource costs than the currency it replaces. Stored value
results in either a net increase or a net decrease in economic welfare depending upon whether average
costs are below or above a certain cut-off. Quantitative restrictions on stored value can be socially
beneficial because they reduce the amount of resources absorbed by the most costly stored value
applications.

*I would like to thank Michelle Kezar for research assistance, James McAfee for useful
references, and Urs Birchler, Marvin Goodfriend, Dave Humphrey, Peter Ireland, Bob King,
Geoffrey Miller, Ned Prescott, Kevin Reffett, Will Roberds, Stacey Schreft, Bruce Summers, and
John Weinberg for helpful comments and conversations. The author is solely responsible for the
contents of this article. The views expressed do not necessarily reflect those of the Federal Reserve
Bank of Richmond or the Federal Reserve System.
**P.O. Box 27622, Richmond, VA 23261, Phone: 804X597-8279, E-mail:
eljml02@rich.fib.org.

Stored value cards look like credit cards but are capable of storing monetary value. There are a
number of stored value card systems being developed in the United States, and some have already been
implemented in Europe and elsewhere. Stored value cards are particularly well-suited for transactions that
would otherwise be carried out with currency, and thus are a private substitute for government fiat money,
like private bank notes. Unlike bank notes, however, stored value cards employ new technologies that are
quite different from, and potentially more costly than, the coins and paper currency they are aimed at
replacing. This paper explores the basic welfare economics of costly private substitutes for government
currency, an important class of payments system innovations2
Consumers and merchants are likely to benefit from the introduction of stored value cards. Many
might prefer to avoid the inconvenience and cost of handling paper currency and coins. The usual
presumption, in the absence of market imperfection, is that a successful new product must provide social
benefits in excess of social costs. Issuers will attempt to cover their costs and earn a competitive return
while providing consumers and merchants with a means of payment they prefer. They can do so if
consumers and merchants are collectively willing to pay, either directly or indirectly, enough to
remunerate issuers for the opportunity cost of the inputs devoted to the alternative means of payment. If
stored value thrives, the standard reasoning suggests, it must be because the value to consumers and
merchants exceeds the cost of provision.
The fact that stored value is a monetary asset provides further reason to believe that it will be
beneficial. Currency is subject to an implicit tax due to inflation, which reduces its rate of return relative
to other risk-free nominal assets. Like any other tax, the inflation tax distorts economic decisions, giving
rise to deadweight costs as people try to economize on the use of currency. Private substitutes for
currency provide a means of avoiding the seigniorage tax, alleviating the deadweight loss associated with
any given inflation rate. Stored value cards can increase economic welfare by easing the burden of
inflation.
Stored value cards could be socially wasteful, however. Stored value liabilities compete with an
asset, currency, that pays no interest, while issuers are free to invest in interest earning assets.3 Thus one
portion of the return to stored value issuers is the spread between market interest rates and the rate of
return on currency. This return far exceeds the government’s cost of producing and maintaining the

21 will use the term “currency” rather than “currency and coin” to refer to government supplied
notes and coinage; the analysis applies pari passu to government-minted coin.
3Under current U.S. regulations, stored value liabilities are treated as bank deposits; reserve
requirements and deposit insurance premia apply.

2
supply of currency--less than two-tenths of a cent per year per dollar of currency outstanding.4 At current
interest rates the private incentive to provide stored value exceeds the social benefit by as much as 4 or 5
percent per dollar outstanding. Thus stored value cards, if successful, will replace virtually costless
government currency with a substitute that could cost substantially more.
In this paper a model in which both currency and stored value are used to make payments is
presented. Stored value cards are provided by a competitive intermediary sector and are used in
transactions for which the cost of stored value is less than the float cost associated with using currency.
Conditions are identified under which the economy with stored value cards does or does not Pareto
dominate an otherwise identical economy without stored value cards. The critical condition is a boundary
on average cost: stored value is beneficial or harmful depending upon whether, other things equal, average
cost is below or above a certain cutoff. If average cost is low, the reduction in the deadweight loss due to
inflation will be large and the resource cost will be low. If average cost is high, the resource cost will be
large and there will be little effect on the burden of inflation.
The fact that costly private substitutes for government fiat money can reduce welfare was
demonstrated by Schreft (1992a), and the model presented below is an extension of hers. This fact should
not be surprising--as I argue below, we should expect the same result in any model with multiple means of
payments5

The interest foregone when holding currency is an opportunity cost to private agents, and they

are willing to incur real resource costs to avoid it. The resource cost of a money substitute is a social cost,
while the interest cost associated with currency is not. Thus the private incentive to provide a substitute
for government currency is greater than the social benefit (Wallace [ 19861). The best policy in the model
is one in which the nominal interest rate is zero--the Friedman rule for the optimum quantity of money
(Friedman [ 19691). For a given positive nominal interest rate, however, Schreft (1992a) has shown that
quantitative restrictions on the use of credit as a means of payment can improve welfare. The same is true
here as well, since stored value is just another form of credit as a means of payment; if nominal interest
rates are positive, then the right kind of quantitative constraints on stored value cards, if practical, can
improve welfare by preventing the most wasteful uses. A noninterest-eaming reserve requirement on
stored value liabilities is inferior to quantitative constraints because it imposes an inframarginal tax on

4 Costs are larger but still quite small for lower denominations: see Lacker (1993).
‘For models of multiple means of payment see Prescott (1987), Schreft (1992a, 1992b), Marquis
and Reffett (1992, 1994), Ireland (1994), Dotsey and Ireland (1995), and Lacker and Schreft
(forthcoming).

3
users of stored value.
No attention is paid here to consumer protection, or to the safety and soundness of bank stored
value activities (see Blinder [ 19951and Laster and Wenninger [ 19951). The analysis presumes that stored
value systems provide relatively fraud- and counterfeit-proof instruments. Historical instances of private
issue of small-denomination, bearer liabilities, such as the early nineteenth century U.S. “free banking”
era, have raised concerns about fraudulent note issue (see Friedman [196O]). Williamson (1992) shows
that a government monopoly in issuing circulating media of exchange may be preferable to laissez-faire
private note issue due to asymmetric information about bank portfolios. Others argue that a system of )
private banknote issue can function rather well: see Rolnick and Weber (1983, 1984). In any case, current
communications technologies and regulatory and legal restraints are quite different from those of the early
nineteenth century. Whether the concerns of Friedman and Williamson are relevant to stored value cards
is beyond the scope of this paper; the focus here is the implication of the seigniorage tax for the private
incentives to provide currency substitutes.

Stored Value Cards
Stored value cards--sometimes called “smart cards”--contain an embedded microprocessor and
function much like currency for a consumer. Value is loaded onto a card at a bank branch, an automated
teller machine (ATM), or at home through a telephone or computer hook-up with a bank. Customers pay
for the value loaded onto the card either by withdrawing funds from a deposit account or by inserting
currency into a machine. Customers spend value by sliding it through a merchant’s device, which reduces
the card’s balance by the amount of the purchase and adds it to the balance on the merchant’s machine.
Merchants redeem value at the end of the day through a clearing arrangement similar to those used for
“off-line” credit card or ATM transactions. The merchant dials up the network and sends in the stored
value, which is then credited to the merchant’s bank account. More elaborate systems allow consumers to
transfer value from card to card.
The stored value on a stored value card is a privately-issued, bearer liability. It is different than a
check because the merchant does not bear the risk of insufficient funds in the buyer’s account. It is
different than a debit card in that the consumer hands over funds upon obtaining the stored value, while a
debit card leaves the funds in the consumer’s account until the transaction is cleared. Thus a debit card is
a device for authorizing deposit account transfers, while a stored value card records past transfers.
For consumers, stored value cards can be more convenient than currency in many settings; some
consumers are likely to find cards physically easier to handle than coins and paper notes. The technology

4
could conceivably allow consumers to load value onto their cards using a device attached to their home
computer, saving the classic “shoe leather” cost of bank transactions. For merchants, stored value cards
offer many of the advantages of credit card sales. The merchant saves the trouble of handling coins and
notes (banks often charge fees for merchant withdrawals and deposits of currency), and avoids the risk of
employee theft. Stored value improves on the mechanisms used for credit and debit cards, however,
because the merchant’s device verifies the validity of the card, without costly and time-consuming on-line
authorization. Thus stored value cards extend the electronic payments technology of credit card
transactions to more time-sensitive settings where on-line authorization is prohibitive.

A Model of Currency and Stored Value
This section describes a model in which stored value and currency both circulate in equilibrium.
Monetary assets are useful in this model because agents are spatiahy separated and communication is
costly. In the absence of stored value, agents use currency whenever shopping away from home and the
structure of the model reduces to a simple cash-in-advance framework. Stored value is a costly private
substitute for currency, similar to costly trade credit in Schreft’s (1992a, 1992b) models.
The model is a deterministic, discrete-time, infinite-horizon environment with a large number of
locations and goods but no capital. At each location there are a large number of identical households
endowed with time and a technology for producing a location-specific good. Each period has two stages.
The first takes place before production and, in principle, allows any agent to trade any contingent claim
with any other agent. During the second stage production and exchange takes place. One member of the
household--the “shopper” --travels to other locations to acquire consumption goods. Simultaneously, the
other member of the household--the “merchant”-produces location-specific goods and sells them to
shoppers from other locations. Shoppers are unable to bring with them goods produced in their own
location, and so direct barter is infeasible.
The fundamental friction in this environment is that it is prohibitively costly for agents from two
different locations to verify each other’s identities. As a result, intertemporal exchange between agents
from different locations is impossible, or, more precisely, not incentive compatible. Meetings between
shoppers and merchants away from home thus effectively resemble the anonymous meetings of the
Kiyotaki-Wright (1989) model. This provides a role for valued fiat currency. Because agents from the
same location are known to each other, households can exchange arbitrary contingent claims with other
households at the same location during the “securities market” in the first stage of each period.
Households could travel to other locations during the securities markets, but anonymity prevents

5
meaningful exchange of intertemporal claims.
me stored value technology is a costly way of overcoming this friction. There are a large number
of agents that are verifiably known to all--call them “issuers.” They are price-takers and thus earn a
competitive rate of return. Like all other agents they can travel to any other location during the securities
market, but since their identities are known they are able to issue enforceable claims. The claim people
want to buy is one they can use in exchange in the goods market. The difficulty facing such an
arrangement, however, is authenticating the claim to the merchant-in other words, the difficulty of
providing the shopper with a means of communicating the earlier surrender of value. Issuers possess the
technology for creating message-storage devices-- “stored value cards”-that shoppers can carry, and
machines that can read and write messages on these devices. Issuers offer to install machines with
merchants, These machines can read, verify and write messages on shoppers’ cards, and can record and
store mestiges itself.
In principle the stored value technology described here could be configured to communicate any
arbitrary messages. In this setting, however, a very simple message space will suffice. The shopper’s
device carries a measure of monetary value, and the merchant’s device deducts the purchase price from
the number on the shopper’s card and adds it to the measure of value stored on the merchant’s device.
During the next day’s securities market, the issuer visits the merchant and verifies the amount stored on
the reader. The issuer sells stored value to households in securities markets and then redeems stored value
from merchants during the next day’s securities markets. Messages in this case function much like the
tokens in Townsend’s (1986, 1987, 1989) models of limited communication. From this perspective,
currency and stored value can be seen as alternative communications mechanisms.
I will adopt a very simple assumption concerning the cost of the stored value technology. I will
assume that the card-reader devices that merchants use are costless to produce but require maintenance
each period, and that only issuers have the expertise to perform this maintenance. The amount of
maintenance required depends on the location in which the device is installed, and is proportional to the
real value of the transactions that were recorded on the device. Some locations are more suited to stored
value systems than others. This assumption will allow stored value and currency to coexist in equilibrium,
with currency used at the locations that are less well-suited for stored value. The proportionality of costs
to value processed might reflect security measures or losses due to fraud that rise in proportion to the value
of transactions. I make no effort to model such phenomena explicitly, but merely take the posited cost
function as given. There are no other direct resource costs. In particular, stored value cards themselves
are costless.

6

The stored value cost function here is quite simple and in many respects somewhat unrealistic.
Merchants’ devices and the communications networks used to”clear” stored value are, arguably, capital
goods and should be represented as investment expenditures rather than input costs. I am abstracting from
capital inputs here, but this seems appropriate in a model with no capital goods to begin with6 Another
feature of my cost function is that cost is proportional to the value of the transaction. In practice, the
resource cost of electronic storage and transmission might not vary much with the numerical value of the
message: transmitting “ten” should not be much cheaper than transmitting “ten thousand.” Thus it seems
plausible that a communications system, once built, would be equally capable of carrying large and small
value messages.7 The cost function I adopt is the simplest one that is sufficient to demonstrate the claim
that the introduction of stored value cards can reduce economic welfare. One critical feature is that the
relative opportunity costs of stored value and currency vary across transactions so that both potentially
circulate in equilibrium. A second critical feature is that there are constant returns to scale in providing
stored value at any given location, so that competition among providers is feasible. It should become clear
as I proceed that the results are likely to carry over to settings with more elaborate cost functions.
The assumed technology also implies that the choice between currency and stored value takes a
particularly simple form. The cost of using currency is the interest foregone while it is in use. The cost of
stored value is simply the resource cost described above. Thus I am abstracting from many of the factors
mentioned in the previous section such as physical convenience, currency handling costs, and employee
theft; I comment on these below. I can now begin describing the model more formally.*

Households

Time is indexed by ~-0, and locations are indexed by z and h, where z,he[O, 1). For a typical
household at location hg[O, l), consumption of good z at time t is given by c,(h,z), and labor effort is given

%ee Ireland (1994) and Marquis and Reffett (1992, 1994) for models with private payment
technologies requiring capital goods.
71reland (1994) studies a similar model in which cost is independent of the value of the transaction.
Also see Prescott (1987).
‘The model is most closely patterned after the environment in Schreft (1992a) and Lacker and
Schreft (forthcoming). The main difference is that here the alternative payments medium is used at a
subset of locations by all shoppers visiting that location, rather than at all locations but by only a subset of
shoppers visiting that location. Also, I allow a general cost function while her cost function is linear in
distance.

7

by n,(h). Households are endowed with one unit of time that can be devoted to labor or leisure. The
production technology requires one unit of labor to produce one unit of consumption good. Household
preferences are
m

ct-ol-W,@),
1-n,(h)),

(1)

where u is strictly concave and twice differentiable. Household preferences are thus Leontieff across
goods. This assumption implies that the composition of consumption is unaffected by the relative
transactions costs at different locations, which considerably simplifies matters. In addition, it implies that
transactions costs at a given location are passed on entirely to shoppers, since demand at a given location is
inelastic.’ Since all goods will bear a positive price in equilibrium, we can assume without loss of
generality that c,(h,z) = c,(h) for all z.
In the securities market households acquire both currency and stored value. Since the units in
which value is stored are arbitrary, there is no loss in generality in assuming that stored value is measured
in units of currency. Thus one dollar buys one unit of stored value. Let c(h,z)

and <(h,z) denote the

consumption of good z at time t purchased with currency and stored value, respectively. Let m,(h) and
s,(h) be the amount of currency and stored value acquired in the securities market at time t. Then the

trading friction implies that

where pr is the price of goods for currency and p:(z) is the price of goods for stored value at location z. 10
Household h sells y:(h) units of output for currency and g(h) units of output for stored value. In

‘Allowing substitution between goods would imply that the composition of consumption varies with
changes in relative transactions costs. Relative prices net of transactions costs would then vary across
locations, destroying the symmetry in households consumption and leisure choices. See Ireland (1994) and
Dotsey and Ireland (1995) for models which relax the Leontieff assumption.
loIn principle the price of goods for currency could vary across locations as well, but symmetry
will ensure equality across locations.

8
addition, they sell y:(h) units of output to issuers. Since issuers are well-known, merchants are willing to
sell to them on credit and accept payment in next period’s securities market. Feasibility requires

ytmVO + y:(h)

+ y,‘(h)

5

n,(h)

(4)

units of stored value on their card reader to be

At the end of the period, the household has pf(h)$(h)

redeemed at t+ 1. Issuers pay interest at the nominal rate it, the market rate on one-period bonds, but
deduct a proportional charge at rate r,(h) from the proceeds to cover their costs. Thus the household
receives (I-r,(h))( 1+ i,)p#)y#)

units of currency at t+ 1 for the stored value they have accepted. l1

Households bring to the securities market: currency from the previous period’s sales, stored value
to be redeemed, maturing bonds, and any currency that might be left over from shopping in the previous
period. Letting b, be bond purchases at t, households face the following budget constraint at time t+ 1.
1
m,+,(h)

+

St+l@)

+

bt+,

5

m,(h)

-

s
0

p,qm(h,W

+

(5)

1
s,(h)

-

s

p:(z)c:(Wdz

+

(1 +i,)b,

+ pt@tm(h)+y,‘(h))

+ (1 -q(h))( 1 +~t)ptS(~)~tS(h)

0

Households maximize (1) subject to (2) through (5) and the relevant nonnegativity constraints, taking
prices and interest rates as given.

Issuers

There are a large number of issuers at location zero, distinct from the households described above.
Their preferences depend on their consumption (4(z)) and leisure (1 - $ according to

’ ‘Note that the payment could be thought of as redemption at par plus a premium (1-r,(h))( 1+ it) 1. The form of merchants’ payments to issuers depends on issuers’ cost functions. The payment is
proportional to the value redeemed because the issuer costs are proportional to value redeemed. If costs
were independent of value redeemed, the equilibrium payment would also be independent of value
redeemed.

9

2t-oPf(Cti- n,?,

=t

i

=

hf..

cti(z)

(6)

Issuers sell s,(z) units of stored value per capita in securities market z at time t in exchange for s&z) units of
currency, and redeem s;(z) units of stored value per capita from merchants at market z at time t+ 1 in
exchange for (1-r,(z))( 1+ iJs;(z) units of currency. All of the stored value they issue will be spent by
households and then redeemed from card readers in equilibrium, so issuers face the constraint
I
s

I

s,(z)dz

=

0

s

s;(z) dz

(7)

0

Maintenance of the devices on which the stored value at location z is redeemed requires

y(z)s~(z)/p~(z)

units of labor effort, where y(z) is a continuous, strictly increasing function with y(0) = 0. Total
maintenance effort is therefore
1
n,

i

=

s
0

YodwP:o

dk

(43)

The alternative for issuers who are not active is to consume nothing (4(z) = rzi = 0), which can be
interpreted as the proceeds of some alternative autarchic activity.
The family of an issuer consists of a worker and a shopper. The worker manages the stored value
business, while the shopper travels around during the goods market period purchasing consumption. Since
issuers are known to all, the shopper can buy on credit, payingp,c’;(z) in the location-z securities market at
t+ 1 for goods purchased there at t. Excess funds are invested in bond holdings $

An issuer’s securities

market budget constraint is

I

l(Z)dz
J0 St+

(9)

I

+

(1 + Qb,’

-

s

(1 + i,)(l - rt(z))&) d.z

0

Active issuers maximize (6), subject to (7) through (9) and the relevant nonnegativity constraints, by
choosing consumption, bonds, labor effort, and how much stored value to issue and redeem at each
location. Because there are a large number of issuers, competition between them will drive the utility of

10
active issuers down to the reservation utility associated with inactivity. Issuers initially have no assets.

Government

The government issues fiat money Mt and one-period bonds Bt and satisfies

MI+1 + B,,

=

Mt

+ (1 + i,P,

(10)

for all t. The government sets a constant money growth rate ‘IC= M,+jM, - 1, where TC1 p - 1.

Equilibrium
A symmetric monetary equilibrium consists of sequences of prices and quantities along with initial

conditions MS1and (1 + i,)B,,

such that households and issuers optimize, the lifetime utility of active

issuers is equal to the lifetime utility of inactive issuers starting at any date, the government budget
constraint (10) holds, and market clearing conditions hold for M,, B,, fl(h), g(h), and y’,(h), for all r and
z. I restrict attention to stationary equilibria, in which real magnitudes are constant over time. Where
possible, time subscripts will be dropped from variables that are constant over time; variables refer to date
t quantities unless otherwise noted.

The first order necessary conditions for the issuer’s maximization problem imply

r(z)(l + i)

=

Y(Z)Pt~Pz%)

(11)

The left side of (11) is the nominal return from issuing one dollar’s worth of stored value at t to be
redeemed at location z at t+ 1, with the proceeds invested in a bond maturing at t+ 1. Interest on the bond
is paid over to the merchant, with a portion r(z) of the payment is deducted as a fee. The right side of (11)
is the nominal cost of enough consumption goods to compensate the issuer for the disutility of maintaining
the stored value device at location z. Thus condition (11) states that marginal revenue equals marginal cost
for stored value issuers.
Merchants consider whether to sell output for currency or for stored value. The first order
necessary conditions for the household’s maximization problem imply that if merchants are indifferent
between accepting currency and stored value, then

11
=

Pt

(1 - 4z))U + Qoz)

(12)

As a result, the last two terms in the household’s budget constraint (5) simplify top~l(h). Households at all
locations face identical terms of trade between consumption and leisure despite the difference in
transactions costs across locations. Consumption and labor supply are therefore identical across locations
and the notation for h can be suppressed.
When shoppers consider whether to use currency or stored value to purchase consumption at
location z, they compare the unit cost of the former, pt, to the unit cost of the latter, pi(z). Using (11) and
(12), shoppers use stored value if
Pt

’

P,“(Z)

pttl + WMl

=

+ 0

(13)

Thus stored value is used where y(z) < i. Because y is strictly increasing, the boundary between the
stored value and the currency locations can be written as a function c(i) = y-‘(i). Stored value will coexist
with currency as long as i is less than y(l), the cost of stored value at the highest cost location. If i 2 y(l),
then stored value drives out currency; in this case C(o is one.
The total resource cost of stored value for a given nominal rate is
I(0
s

y(z)&

5

r(i)

(14)

0

Steady-state equilibrium values of c and n can be found as the solutions to the first order condition
u,(c,l -n)lu&c,l -n)

=

1

=

c(1 + l?(i)).

+

(1 - C(i))i

+

r(i)

(15)

along with the feasibility condition
n

(16)

For a given nonnegative nominai interest rate, consumption and employment are determined by (15) and
(16). l2 Assuming that neither leisure nor consumption are inferior goods, then v(c, l-n) =

12The reduced form structure in (15) and (16) is identical to Schreft (1992a) and Lacker and
Schrefi (forthcoming), although the models are somewhat different. In her model households use credit

12
uI(c, 1-n)lr+(c, l-n) is decreasing in c and increasing in l-n. If in addition we assume that v(c, l-n) goes to
infinity as c goes to zero and zero as l-n goes to zero, then we are guaranteed an interior solution; the
proof appears in the appendix. The real interest rate is p“ - 1 in all equilibria, and the inflation rate is
P(l+O - 1.
Without stored value cards the economy has the same basic structure as a standard cash-in-advance
model (Lucas and Stokey [ 1983]), and can be obtained as a special case in which C(i) (and thus I’(i)) equals
zero.

The Welfare Economics of Stored Value
An optimal steady state allocation is defined by the property that no other feasible steady state
allocation makes at least one type of household better off without making some other type of household
worse off. Two features of the model make optimality relatively easy to assess. Even though at some
locations goods are sold for currency and at other locations goods are sold for stored value, households at
all locations face identical terms of trade between consumption and leisure. As a result, all households at
all locations will have the same lifetime utility in any given equilibrium. We can therefore focus our
attention on the well-being of a representative household at a representative location. Second, because the
lifetime utility of any given issuer is zero in all equilibria, we can effectively ignore the welfare of issuers
when comparing equilibrium allocations. This just reflects the fact that issuers receive a competitive rate
of return and are indifferent as to how they obtain it; constant returns to scale in providing stored value at
any location implies that issuers earn no rents. Given these two facts, we can compare alternative
i
allocations by considering their effect on the lifetime utility of a representative household.
For the version of this economy without stored value the welfare economics are well known.
Households equate the marginal rate of substitution between consumption and leisure to 1 + i rather than 1,
the marginal rate of transformation, because consumption is provided for out of currency accumulated by
working in the previous period and currency holdings are implicitly taxed at rate i. Optimal@ requires
that the marginal rate of substitution equal the marginal rate of transformation, which only holds if the
nominal interest rate is zero. A positive nominal interest rate distorts household decisions, inducing
substitution away from monetary activity (consumption) toward nonmonetary activity (leisure). The

when close to their own home location and currency when farther away; thus at every location shoppers
from nearby use currency and shoppers from a distance use cash. In contrast, at some locations only
stored value is used and at other locations only currency is used in my model. Also, in her model credit
costs are linear in distance.

13
resulting welfare reduction is the deadweight loss from inflation in this model. Intuitively, inflation
reduces the rate of return on currency, which causes consumers to economize on the use of currency. In a
cash-in-advance economy they can do this only by consuming less of the goods whose purchase requires
currency. The optimal monetary policy is to deflate at the rate of time preference, x = Q - 1, so that the
nominal interest rate is zero and the distortion in (15) is completely eliminated (Friedman [1969]). Note
that in the absence of stored value, inflation has no effect on the feasibility frontier (16).
I will compare two steady-state equilibria with identical inflation rates, one with and one without

stored value. Since the real rate is the same in all equilibria, the nominal rate is constant across equilibria
as well. Stored value has two effects on a typical household’s utility. The first is to alter the marginal rate
of substitution between monetary and nonmonetary activities. The transactions cost associated with
purchases using stored value at a given location z C c(z) is y(z), which is less than i, the private opportunity
cost associated with using currency: see Figure 1. Thus stored value reduces the average transactions cost
associated with consumption goods. This can be seen from (15), noting that the average cost of stored
value, I?(i)lC(z),is less than i. Stored value reduces the right side of (15) by the amount C(i) - I’(&
shown as the region A in Figure 1. Therefore, stored value cards reduce the distortion caused by inflation.
By itself, this increases welfare. Note that the lower the total cost of stored value r(i), holding constant i
and c(o, the larger the welfare gain from stored value.
The second effect is through the feasibility constraint. Stored value cards involve real resource
costs. Maintenance of the technology requires issuers’ labor time, and consumption at every location must
be diverted to compensate issuers for their effort. Currency requires no direct resource costs in this
model. l3 The introduction of stored value shifts the consumption-leisure feasibility frontier (16) inward,
since resources must be diverted to cover the real costs of stored value. The area under y(z) from zero to
C(r) in Figure 1 is equal to r(i), the real resource costs devoted to stored value activities. In contrast, the
opportunity cost associated with currency (the area under i) is merely a transfer payment. By itself, the
resource cost of stored value reduces welfare; a virtually costless government money is replaced by a
costly private money. Note that the larger the total cost of stored value (holding constant i and C(i)), the
larger the reduction in welfare.
The net effect of stored value cards on economic welfare is indeterminate, and depends on the
structure of stored value costs across locations. Since we are comparing two equilibria with the same

13This assumption is for convenience only. The essential property is that the government cost of
currency is small relative to government proceeds from the seigniorage tax on currency. See Lacker
(1993) for a similar model in which the provision of currency is costly.

14
nominal interest rate, we know that the marginal location has a cost of i. But conditions (15) and (16) tell
us that the effect depends on the shape of the cost function. The benefit of stored value in (15) varies
positively with the area A in Figure 1. The detrimental effect of stored value in (16) varies positively with
r(i). Both effects depend solely on I?(i) for any given i and S(f). If costs are low across most locatior~~but
then rise sharply-for example, if y is quite convex-then l?(o will be relatively small. In this case the
negative effect through the feasibility condition will be small, and the positive effect through the marginal
rate of substitution, c(i)i - I?(i), will be large. If instead costs are large at most locations--for example, if y
is quite concave--then r(i) is close to <(i)i, the resource costs will be large, and the gain from reducing the
marginal rate of substitution will be small. Thus the greater the convexity of costs across locations, the
more likely it is that stored value cards improve economic welfare. This intuition is formalized in the
following proposition. (The proof appears in the Appendix.)

Proposition 1: Fix i. Compare an economy with no stored value to an arbitrary stored value economy
with a given ratio of stored value to currency, C(i)l(l-c(i)).

There is a cutof I’* [which depends on i and

C(i)] such that if l?(i) > I’* then wel&zreis lower in the stored value economy, and if JI’(o c I’* then
wel@re is higher in the stored value economy.

The principle described in Proposition 1 appears to be quite general. In any model in which there
is a deadweight loss due to the inflation tax, a private substitute for currency will reduce the base on which
the tax is levied. The cost of the substitute must be less than the tax it evades--otherwise it would not be
introduced. Holding constant the tax rate (the nominal interest rate), the incidence of the tax is lower and
so the deadweight loss associated with that distortion will fall. Thus in any model we should expect private
substitutes for fiat money should help reduce the burden of a given inflation rate.
The negative welfare effect of stored value cards would seem to generalize as well. The spread
between the return on currency and the return on interest-bearing government debt is a tax on currency.
Absent regulatory constraint, capturing this spread is a component of the return to any private scheme that
provides a substitute for currency. Absent market imperfection, participants will adopt stored value if
their collective benefits exceed their collective costs. But their net benefits differ from social net benefits
in two ways; the capture of seigniorage is not a social benefit, and they do not bear the governmental cost
of currency provision. The gap between the nominal interest rate and the government’s per-dollar cost of
providing currency thus represents the excess incentive to implement currency substitutes. Private
providers will be willing to devote this excess to real resource costs, but these are wasteful from society’s

15
point of view, since they represent costly avoidance of the seigniorage tax.
More realistic or elaborate models would also display the principle described in Proposition 1.
For example, if stored value costs do not depend directly on the value of messages then the fee an issuer
collects from a merchant would be independent of the merchant’s sales.14 The relevant cost comparison is
then between the cost of the seigniorage tax, which is proportional to production, and the fixed fee, which
is not. In this case the set of locations using stored value would vary with equilibrium consumption,
instead of being independent of consumption as in the model above. Nevertheless, stored value would
reduce transactions costs where it is used, and the benefit of a reduced inflation tax burden would have to
be weighed against the added resource costs.
In the absence of stored value, inflation is costly in the model because it distorts the choice
between monetary and nonmonetary activities. Some economists have suggested that an important cost of
inflation is that it encourages costly private credit arrangements as substitutes for government money (see
Ireland [ 19941, Dotsey and Ireland [ 19951, Lacker and Schreft [forthcoming], and Aiyagari, Braun and
E&stein [ 19951). Stored value could reduce this cost of inflation by displacing more costly means of
payment such as checks or credit cards. The social benefit of stored value would then also include the
reduction in payments cost for some transactions, and this benefit would be larger the smaller is the cost of
stored value. But again, the benefit of stored value would have to be weighed against the resource cost of
substituting stored value for virtually costless currency. Something like Proposition 1 would again emerge;
the lower the average cost of stored value cards, the greater the gain from displacing more costly means of
payments and the smaller the resources diverted to stored value systems.
As I mentioned earlier, stored value seems likely to offer consumers and merchants greater
physical convenience or some other advantages over currency that are not captured in the model presented
above. Such advantages would not alter the basic feature of Proposition 1, however. If merchants find
stored value less costly to handle than currency, their savings will presumably be reflected in their
willingness to pay stored value issuers and the social benefit of stored value to merchants will be reflected
in issuers’ revenues. Similarly, consumers find stored value more convenient than currency, they should
be willing to pay, either directly or indirectly and the benefit of stored value to consumers will be reflected
in issuers’ revenues. The intrinsic superiority of stored value cards will provide issuers with added
incentive to provide stored value, but the nominal interest rate (minus the resource cost of providing
government currency) still measures the excess of the private return to issuing stored value over social

“The payments technology in Ireland (1994) has this property.

16
benefits.
What if consumers could earn interest on their stored value cards, a possibility that appears to be

technologically feasible? In this case issuers’ net interest margin would be the difference between the Tbill rate and the rate paid on stored value. This margin will not exceed the marginal cost to the issuer of
providing stored value. But if stored value pays interest and coexists with noninterest-bearing currency,
then it must be the case that consumers, at the margin, find stored value less convenient than currency;
they are being paid to use stored value. The rate consumers earn on stored value reflects the marginal
social cost of the added inconvenience of stored value. The total marginal cost of stored value,
aggregating across consumers and issuers in this case, is the nominal interest rate--the sum of the rate paid
to consumers and the net interest margin of issuers. The seigniorage tax captured by issuers may be
passed on, in part, to consumers in the form of interest on stored value card balances. This would
compensate consumers for incurring added costs to adopt stored value. But the nominal interest rate still
measures the excess private incentive to adopt stored value.
What if stored value completely displaces currency ? In this case the meaning of the nominal
interest rate in the model becomes somewhat ambiguous; because currency does not circulate it might not
serve as unit of account. Nonetheless, the difference between the real return on bonds and the real return
on stored value liabilities will not exceed the marginal cost of providing stored value.15 Unless this
difference is less than the government’s cost of providing currency, the principle underlying Proposition 1
still applies.
Bryant and Wallace (1984) have argued that different rates of return on different government
liabilities can be justified as an optimal tax. If all sources of government revenue require distortionary
taxation, then it may be beneficial to raise some revenues from the taxation of currency holders. This
consideration is not captured in the model described above, The seigniorage tax merely finances interest
payments on government bonds. The reduction in seigniorage revenues was offset by a reduction in
outstanding government debt, keeping the nominal rate constant. If instead the loss of seigniorage had to
recovered by raising other distortionary taxes, it would strengthen the case against stored value. The
additional deadweight burden of the compensating tax increases would have to be added to the resource
cost of stored value. Similarly, nonzero government expenditures financed, in part, through seigniorage

“This could happen in one of two ways. Currency could remain the unit of account--a “ghost
money.” Issuers would pay interest to consumers on stored value, and the net interest margin would not
exceed the marginal cost of stored value. Alternatively, stored value could become the unit of account, in
which case the nominal interest rate would fall to the marginal cost of stored value.

17
would not change the basic feature Proposition 1.

Policy
In the presence of one distortionary tax a second distortion can sometimes improve economic
welfare. A positive nominal interest rate is a distortio~ry

tax on holders of government currency. In the

laissez-faire regime with stored value, welfare can be lower because of the costs of stored value, which
suggests that constraints on the issue of stored value cards might be welfare-enhancing.

This turns out to

be true. Restrictions on the issue of stored value can improve welfare, in this second-best situation, by
reducing the costly displacement of government currency.
Consider first a simple quantitative restriction on the use of stored value. Imagine a legal
restriction that limits the quantity of stored value used by households, or, equivalently, that limits the
locations at which stored value is accepted. Households can only make a fraction 51of their purchases
using stored value, where the government sets r\ between 0 and C(i). Households will continue to use
stored value where it is most advantageous to do so-at locations 0 through q. At locations ?J through 1
households use currency. Equilibrium is still characterized as the solution to (15) and (16), except that C(i)
is replaced by q. For a given nominal interest rate, consumption and employment are determined as the
solutions to

tl

u,(c, 1-n)/u,(c, l-n)

=

1

+

(1 - q)i

+

(17)

s Y(W
0

'I

n

=

c[l

+

s Y(Z)&1

(18)

0

Define C($I and n(q) as the solutions to (17) and (18) for r\~O[,<(i)], and v(q) z u(c(q), l-n(q)).

The

function v($ is the utility of a representative household under the constraint that no more than a fraction q
of purchases can be made using stored value.

Proposition 2: v ‘(c(i)) < 0, and therefore there is a binding restriction q c r;(i) on stored value under
which steady state utility is higher than under the laissez-faire regime.

18
Reducing q marginally below c(i) has two effects. The direct effect via the resource constraint (18) is to
eliminate the most costly uses of stored value, allowing greater consumption at each level of employment.
The increase in utility at q = c(i) is proportional to y(i). The second effect via the marginal rate of
substitution is to substitute currency (transactions cost r) for stored value (transactions cost y(?j)). The fall
in utility is proportional to i - y(q), which vanishes at r\ = C(i) = y“(i), since at the margin stored value
and currency bear the same transactions cost. The first order resource savings dominates the negligible
increase in the burden of inflation. The net effect of decreasing tl is positive. Therefore there must be a
value q c C(i) that results in higher steady state utility than the laissez faire regime. Note that Proposition
2 holds whether or not the stored value equilibrium is worse than the no-stored-value equilibrium; even if
store value is welfare-enhancing, quantitative constraints would still be worthwhile. l6
An alternative method of restraining stored value is to impose a reserve requirement.

Issuers are

required to hold currency equal to a fraction 8 of their outstanding stored value liabilities. Issuers earn (l6)i rather than i on their assets, and the cost of foregone earnings, 6i, is passed on to merchants and

ultimately to consumers. Stored value is used at fewer locations for any given interest rate-only where
y(i) C (l-6)i. Raising the reserve requirement from zero reduces the amount of resources diverted to
stored value. By itself this increases utility by easing the feasibility frontier in (18). The first order
condition (15) becomes
C&b)

u l(C,1 -n)/u,(c, 1-n)

=

1

+

(1 - C(i,G))i

+

s

0

(1 -q-‘y(z)dz

(19)

where C(i,S) = y-*[( I-S)z’J. Increasing the reserve requirement now has two effects on the marginal rate of
substitution. First, raising 6 increases the locations at which currency rather than lower cost stored value
is used. This effect operates through C(i,b) in (19). Second, raising 6 increases the transactions cost at all
locations at which stored value is used. This effect increases the integrand in the last term in (19) and does
not vanish at 6 = 0. The first effect is identical to the effect of decreasing the quantitative constraint 11in
(17). The quantitative constraint does not involve the second effect in (19), since it leaves inframarginal

16Proposition 2 parallels Proposition 2 in Schreft (1992a). In her model the government issues no
bonds and government expenditure depends on the seigniorage collected. Lowering the constraint holding
the inflation rate constant increases the demand for money and thus government expenditures. Her
proposition requires the condition that government expenditures rise by less than the resource cost of
payments services fall when the constraint is tightened. This condition is unnecessary if government
spending is held constant and instead the bond supply varies across equilibria. There are no government
expenditures in my model.

19
stored value users unaffected. In contrast, the reserve requirement imposes a tax on all stored value users.
Therefore, a quantitative constraint is superior to a reserve requirement in this environment.

A reserve

requirement improves welfare only if the second effect in (19) does not dominate.

Concluding Remarks
When the nominal interest rate is positive, there is an incentive to develop substitutes for
government currency. This incentive is likely to exceed the social benefit of such substitutes because the
private opportunity cost of holding currency is larger than the social cost of providing currency. Although
stored value can lower the opportunity cost of payments media for inframarginal consumers, the real
resources diverted to stored value are wasteful from society’s point of view. For a given nominal interest
rate, stored value cards are good or bad for welfare depending upon whether the average cost of stored
value is below or above a certain cut-off. Quantitative restrictions on stored value are socially beneficial,
in this second-best situation, because they reduce the amount of resources absorbed by the most costly
stored value applications. I do not claim to show that such restrictions can be easily implemented--only
that if such restrictions were practical, they would enhance welfare.
Neil Wallace (1983) pointed out that the U.S. government has effectively prohibited private issue
of paper smalldenomination

bearer notes, such as bank notes. In the absence of such a ban, he argued,

private intermediaries could issue perfect substitutes for government currency backed by default-free
securities such as U.S. Treasury bills. In this case one of two things could occur. Either the nominal rate
of return would not exceed the marginal cost of such intermediation, which he reckoned at close to zero,
or government currency would cease to circulate. Stored value cards are just another way of issuing
smalldenomination,

bearer liabilities. As a corollary to Wallace’s thesis, then, we should expect one of

two things to happen. Either the nominal interest rate will not exceed the marginal cost of an additional
dollar’s worth of stored value, or government currency will cease to circulate. All I have added to
Wallace’s argument is the observation that since stored value employs a technology that is different from,
and potentially far more costly than, the government currency it would replace, it is possible that either
outcome could reduce economic welfare.
The restrictions that have prevented private paper substitutes for currency were in place since at
least the end of the Civil War. As Wallace (1986) notes, “(i)f there is a rationale for that policy.. . then it
would seem that it would apply to other payments instruments that potentially substitute for the monetary

20
base.” These longstanding restrictions on paper note issue evidently have been repealed.17 Current policy
thus avoids the inconsistency of allowing electronic substitutes for government currency while preventing
paper substitutes.

t7Title VI of the Community Development Banking Act, P.L. 103-325 (1994) repealed all
restrictions on note issue by National Banks except the l/2 percent semi-annual tax on outstanding notes.
Section 1904(a) of the Tax Reform Act of 1976 repealed the 10 percent tax on note issue by corporations
other than ~ti0~1 banks. De facto restrictions by bank regulators may still prevent private note issue.

21

APPENDIX

Existence: Define c(y) and n(y) as the joint solutions to UJC, l-n) = qu2(c, l-n) and qc + (l-n) =
y. The assumptions on preferences imply that c(y) and l-n(y) are unique, strictly positive for y > 0,
0

continuous, and monotone increasing. Therefore there exists a unique y such that n@) = q&Q.

Proof of Proposition 1: Define c(q,r) and n(q,r) as the unique solutions to
u&c,1 -n)

=

4 Qc, 1-n)

n

=

rc

where attention is restricted to rz 1 and qzr. Define V(q,r) = u(c(q,r),l-n(q,r)).

It is easy to show that

since neither leisure nor consumption is an inferior good, V is strictly decreasing in q and r.
The first-best allocation has a nominal interest rate of zero, so q = r = 1. Economies with
positive nominal rates but no stored value have q = 1+i > 1 and r = 1. For given i and C(i), q and r
vary positively with the aggregate r(i). This amounts to varying average cost holding constant marginal
cost at location 2 = c(i). Note that l?(i) can lie anywhere in the interval (O,C(i)i). Define w(r) =
V(l+(l-C(z))i+r,l+r).

Then w(0) = V(l+(l-c)i,l)

> V(l+i,l),

and w([;(i)i) = V(l+i,l+<(i)i)

C

V(1+i, 1). Since w(r) is strictly decreasing in r, it follows immediately that there exists a unique r* for
which w(I@) = V(l+i,l).

cl

Proof of Proposition 2: Define q(q) as the right side of (17), and r(q) as the bracketed term in
(18). With v(rl) = V(q(M,r(W),

we have li~,ctij

v’01) = Ii%-<(i)

V,.y(<(i)) = v,y(<(~J) < 0, since y(C(i)) = i and V,. < 0.

lv&’

+

V/l = V,[Y(~(OVI +
0

Figure 1 Opportunity Costs for Currency and Stored Value Across Locations

costs

i

0

GO?

Locations, z

22
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