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FRBSF

WEEKLY LETTER

December 5, 1986

Forecasting Oil Prices
The sharp decline in oil prices over the last 12
months has greatly reduced the actual rate of
inflation in the United States, and served as a
renewed reminder of the importance of forecasting the future behavior of oil prices as part of
any forecast of the general rate of inflation. The
economic theory of futures markets suggests that
oil futures prices may provide information useful
in forecasting future oil prices.
This Letter examines the forecasting ability of
futures prices for oil. Specifically, prices on
three- and six-month futures contracts for crude
oil since August 1983 are compared with the
subsequent spot prices - the price of oil for current delivery - three and six months in the
future.
Several conclusions emerge from this comparison. First, oil futures prices during the period
examined are as likely tounderpredict as to
overpredict future spot prices. In technical
terms, they are unbiased.
Second, futures prices provide relatively inaccurate forecasts of future spot prices even though
they are unbiased. Forecast errors may, on average, be equal to zero, but this result tends to
reflect large positive and large negative errors
that cancel each other out.
Third, futures prices seem to provide somewhat
more accurate forecasts than current and past
spot prices. Finally, incorporating information
on the relationship between current futures
prices and the current spot price improves the
forecast.

Oil futures prices
Futures markets exist to enable individuals and
firms to reduce the risk of future price movements. A firm that knows it will need oil in the
future has two choices. It can wait until it needs
the oil to purchase it, and then buy at an uncertain future price in the spot market. Or it can
contract today at a known price in the futures
market for later delivery. For example, if the firm
needs oil in three months, it could makethe pur-

chase at today's three-month futures price and
eliminateuncertainty about the actual cost of
the oil in three months time.
The desirability of buying, or selling, oil in the
futures market will depend on the futures price
relative to the expected future spot price. If the
spot price were expected to rise above the current futures price, buyers would have an incentive to buy in the futures market rather than to
wait to buy in the spot market. This process
would tend to bid the futures price up. Similarly,
a futures price higher than the expected future
spot price will tend to place downward pressure
on the futures price. Futures prices will also be
related to the current spot price and the cost of
carrying inventories of oil over the relevant time
horizon.
This analysis suggests that futures prices should
provide forecasts of future spot prices. Economists would describe the futures market for oil
as efficient if the forecast of future spot prices
implicit in futures prices incorporates all currently available relevant information. Futures
prices by their very nature are forward-looking.
The October three-month futures price for crude
oil, for example, should provide a good forecast
of the spot price that will prevail in January.
Despite their forward-looking nature, crude oil
futures prices vary closely with the current spot
price. This is illustrated in Chart 1, which plots
the spot price of West Texas crude from August
1983 to October 1986, and the three-and sixmonth futures prices. (All prices are measured as
of three business days before the 25th of each
month. This corresponds to the settlement date
for delivery during the following month since
pipeline space must be reserved by the 25th of
the month.)
The close relationship between all three price
series apparent in Chart 1 might suggest that
futures prices would not provide much more
information about future spot prices than do current spot -prices. Nevertheless, the market would

FABSF
still be efficient if one generally could not predict changes in the spot price of crude oil at
horizons of three and six months. In this case, a
rise in the current spot price should lead to an
equal upward revision in forecasts of future spot
prices and currentfutures prices since the rise
would not be expected to be reverse&JHuture
changes were unpredictable, the spot price in an
efficient market could be characterized as following a random walk.

Chart 1
Spot and Futures Oil Prices Vary Closely
$!Barrel

r

"28 I.
24

20

16

Evaluating forecast accuracy
Two basic issues are involved in evaluating the
forecast accuracy of futures prices. The first is
whether the forecasts are unbiased in the sense
that they do not systematically under- or overestimate future spot prices, and the second is the
size of the actual forecast errors.
If the forecasts from futures prices were
unbiased, the subsequent actual spot prices
should be above the current futures prices as
often as they are below them. This means that,
in a plot of the three-month futures price against
the spot price3 months later, all the points
should fall roughly along a45° line that represents an exact match between the forecast and
the actual spot price.
Chart 2A provides such a plot for the threemonth futures pricei Chart 2B plots the sixmonth futures price against the actlJal spot price
six months later. In general, the points do seem
to fall alongthe 45° lines, indicating that the
forecasts are unbiased. The few points well
below the 45° line are associated with the rapid
decline in spot prices during 1985 when futures
prices consistently indicated less of a decline in
future spot prices than subsequently occurred.
Statistical tests support the conclusion that, over
the sample period,futures prices were unbiased
forecasts of future spot prices.
Just because a forecast is right on average does
not mean that it is a very accurate forecasLLarge
positive errors may simply offset large negative
errors. Chart 3 shows the errors one would have
made using the futures prices as forecasts of
future spot prices. The failure of futures prices to
predict the full decline during late 1985 and
early 1986 is readily apparent. Earlier in 1985,
positive errors were common. These forecast
errors are large relative to the level of spot
prices, which averaged $28 in 1985 and $15
during the first ten months of 1986.

12

8 ' - - - - - - ' - - - - - - - ' - - - - - - - ' - - - - -.....
1983

1984

1985

1986

More accurate
Even though futures prices and spot prices tend
to move together, futures prices may still provide
a better forecast of future spot prices. A direct
comparison of the predictive accuracy of futures
prices with that of forecasts based only on current and lagged spot prices yielded two interesting results. First, futures prices do provide better
forecasts, as ranked by a measure of their forecast errors.
Second,· based on current and lagged spot
prices, forecasts of future spot prices for forecast
horizons of three months or more are all equal.
Thus, the bestforecast of the spot price six
months in the future is the same as the best forecast of the spot price three months in the future.
The six-month futures price, as a forecast of the
spot price in six months, should therefore
roughly equal the three-month futures price
since the latter is a forecast of spot prices in
three months. This helps explain why the threeand six-month futures prices move together so
closely, and it supports the hypothesis that the
pattern of spot price behavior is close to a ran~
dom walk at these horizons.

Improving the forecast
Forecasts of future spot prices can be improved
by taking the relationship between current spot
and futures prices into account. Specifically,the
future change in the spot price should be related
to the difference between the futures price and
the current spot price. If spot prices were
expected to rise, for example, futures prices
should be higher than the current spot price,

Chart 2
Oil Futures Prices are Unbiased Forecasts of
Future Spot Oil Prices

Chart 3
Large Forecast Errors from Oil Futures Prices
Dollars

Future

Spot Price

A. 3-Month l7utures Prices

8

40
35

4

30

6-Month
Futures Price

3-Month
Futures Price

A

25
0

20
15
10

-4

5
0""--I....---l_...L---l._...L-~_-'--'

o

5

10

15

20

25

30

35

40

-8

Futures Price

Future

Spot Price

B, 6-Month Futures Prices

-12

40
35

-16

30

1983

25

1984

1985

1986

20

.;

15
10

5
0""--I....---l_...L---l._...L-~--'---'

o

5

10

15

20

25

30

35

40

Futures Price

although never by more than the cost of carrying
inventories over the same horizon. Forecasts
derived using this difference between current
spot and futures prices have smaller forecast
errors than forecasts based just on the futures
prices themselves.

Conclusion
On the basis of the estimated relationship
between future changes in spot prices and the
differences between current spot and futures
prices, forecasts of crude oil prices for January
1987 and April 1987 can be calculated from
October spot and futures prices. On the 21 st of
October, the spot price for West Texas crude oil
was $14.80. The three- and six-month futures
prices were both $15.52.

Based on these data and a relationship between
futures and spot prices derived from historical
data, the forecast is $15.86 for the January spot
price and $15.84 for the April spot price.
However, the accuracy of such forecasts is very
low and, at best, the historical relationships only
allow one to say that, with 95 percent certainty,
spot prices next January and April will be somewhere in the $5~$25range.
These large margins of error in forecasts of future
oil prices imply that market participants concerned with the future course of oil prices face a
high level of uncertainty. During the past fifteen
years, the market for oil has been dominated by
political developments. Such influences are
inherently difficult to predict, and for that reason, it is perhaps not surprising that oil price
forecasts are so inaccurate.

Carl Walsh

Opinions expressed in this newsletter do not necessarily reflect the views of the management ofthe Federal Reserve Bank of San
Francisco, or of the Board of Governors of the Federal Reserve System.
Editorial comments may be addressed to the editor (Gregory Tong) or to the author ..•. Free copies of Federal Reserve publications
can be obtained from the Public Information Department, Federal Reserve Bank of San Francisco, P.O. Box 7702, San Francisco
94120. Phone (415) 974-2246.

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BANKING DATA-TWELFTH FEDERAL RESERVE DISTRICT
(Dollar amounts in millions)

Selected Assets and Liabilities
Large Commercial Banks
Loans, Leases and Investments1 2
Loans and Leases1 6
Commercial and Industrial
Real estate
Loans to Individuals
Leases
U.S. Treasury and Agency Securities 2
Other Secu rities 2
Total Deposits
Demand Deposits
Demand Deposits Adjusted 3
Other Transaction Balances4
Total Non-Transaction Balances 6
Money Market Deposit
Accounts-Total
Time Deposits in Amounts of
$100,000 or more
Other Liabilities for Borrowed MoneyS

Two Week Averages
of Daily Figures

Amount
Outstanding

Change
from

11/12/86

11/5/86
239
519
194
61
44
6
259
21
2,591
2,439
189
40
193

203,358
182,688
50,076
67,061
39,476
5,590
12,779
7,891
210,324
57,598
38,015
18,358
134,368

-

46,328

-

64

32,925
25,504

-

131
472

Period ended

Change from 11/13/85
Dollar
Percent? '

-

-

-

5,829
4,055
1,360
1,352
1,633
194
1,134
639
7,208
7,162
8,156
3,814
3,767

2.9
2.2
- 2.6
2.0
4.3
3.5
9.7
8.8
3.5
14.2
- 17.6
26.2
- 2.7

656

1.4

5,663
1,258

- 14.6
5.1

Period ended

11/3/86

10/20/86

21
64
42

59
12
48

Reserve Position, All Reporting Banks
Excess Reserves (+ lJDeficiency (-l
Borrowings
Net free reserves ( + )JNet borrowed( - l

1 Includes loss reserves, unearned income, excludes interbank loans
Excludes trading account securities
3 Excludes
government and depository institution deposits and cash items
4 ATS, NOW, Super NOW and savings accounts with telephone transfers
S Includes borrowing via FRB, TT&L notes, Fed Funds, RPs and other sources
6 Includes items not shown separately
7 Annualized percent change
2

u.s.