Oil price increases and decreases seem to have asymmetric effects:
'via Blog this'
Nota: l' asimmetria è incompatibile sia con mercati concorrenziali sia con mercati monopolistici. inoltre i mercati del petrolio non sembrano monopolistici.
Stephen P. A. Brown and Mine K. Yücel sono forse i maggiori esperti in materia
https://www.dallasfed.org/assets/documents/research/efr/2000/efr0003b.pdf
Evidentemente è legata ad altre situazioni:
Beyond market power and search costs,
economists have offered a number of explanations
for the asymmetric response of gasoline
prices to movements in crude oil prices. Alternative
explanations include markups that vary
over the business cycle, consumer response to
changing prices, inventory management,
accounting practices, and refinery adjustment
costs.
If markups vary over the business cycle,
the difference between the crude oil and retail
gasoline price could increase as overall prices
rise. Reagan (1982) and Reagan and Weitzman
(1982) offer a theoretical explanation for such
a relationship based upon the variation in demand
over the business cycle. Haltiwanger and
Harrington (1991) further suggest that the fluctuations
in margins may result from variations in
the degree of collusive behavior. However, BBY
find that the shocks to crude oil and gasoline
prices originate with supply rather than demand,
which renders the explanation inapplicable
The consumer response to changing
gasoline prices may contribute to the asymmetry
between movements in crude oil and gasoline
prices at the retail level. If consumers accelerate
their gasoline purchases to beat further increases
when its price is rising, they will increase inventories
held in automobiles and quicken the pace
at which the price rises. If drivers fear running
out of gasoline and do not slow their purchases
when its price is falling by as much as they
accelerated their purchases when prices rose,
the price of gasoline will fall more slowly than
it rose.
Similarly, firms in the oil industry may
view the short-run costs of unexpected changes
in their inventories as asymmetric (see BCG). If
operation costs rise sharply when inventories
are reduced below normal operating levels, a reduction
of upstream supply could lead a firm to
raise its output prices aggressively to prevent a
loss of inventories. If an increase in inventories
above normal operating levels has a relatively
small effect on costs, the firm could be less
aggressive in reducing its selling prices when it
experiences an increase in upstream supply.
Hence, inventories would buffer downstream
price movements less when prices are rising
than when they are falling.
If oil supply shocks cause asymmetric
movements in inventories—with higher inventories
when oil supply is plentiful and lower
inventories when oil supply is reduced—the
asymmetry of price movements could be
enhanced by FIFO (first in, first out) accounting.
If inventories are lower when upstream supply
is reduced, the firm will sell the products incorporating
the higher upstream price sooner. If
inventories are higher when upstream supply is
increased, the firm will sell the products incorporating
the lower upstream price later. These
actions help foster asymmetric pricing Refiners also face adjustment costs to
changing their output or their product mix and,
consequently, adjust their output slowly when
possible. When crude oil supplies are reduced,
refiners as a group have little choice but to
reduce output quickly, which would lead to
fairly quick increases in gasoline prices. When
crude oil supplies are increased, however, refiners
don’t necessarily have to increase output
quickly. They can increase output slowly and
delay the decreases in gasoline prices.
Furthermore, Peltzman finds that an asymmetric
relationship between an upstream and
a downstream price is as likely in competitive
markets as in markets thought to be monopolized.
If competitive market forces and asymmetry
coexist, steps to suppress or eliminate the
asymmetry are likely to prove costly.
Spiegazioni alternative:
1) Ciclo. Il prezzo del petrolio diminuisce in tempi di vacche magre, quando il mark up è già al limite e non tollera altre diminuzioni
2) Inventari. Quando si prevede un aumento si tende a comprare di più oggi favorendo ulteriormente l' aumento previsto. Quando si prevede una diminuzione si fa lo stesso ma non nella stessa misura visto che il minimo indispensabile va ugualmente comprato oggi.
3) Politiche. Una diminuzione della materia prima varia i mix dei prodotti venduti e si temporeggia sulle politiche di prezzo. Cosa non possibile in caso di aumento.
4) Trend. Poiché il petrolio è una risorsa scarsa il cui prezzo tende storicamente all' aumento, in caso di diminuzione del prezzo si tende a temporeggiare poiché le probabilità di un ritorno alla tendenza storica sono maggiori.
