Gasoline inventories reached the highest level in a year last week, signaling weakening demand.

Inventories rose by more than 8 million barrels versus expectations for gains of more than 2 million barrels, according to data released by the Energy Information Administration.

Winter is a seasonally slow season for gasoline, as snowstorms and cold weather impact driving habits. However, the surge in inventories appears to be outsized, equaling the largest two-week build since 2016.

"Gasoline prices will come under pressure," Andy Lipow of Lipow Oil Associates told Yahoo Finance on Wednesday. "On the other hand, we are just starting with the refinery maintenance season, which will reduce supply."

The national average for retail gasoline was at $3.08 per gallon on Wednesday, down from $3.28 a year ago.

Inventories of distillate fuels, which includes diesel, also grew by 6.5 million barrels versus expectations of 1.7 million. Diesel stockpiles are at their highest level since 2021.

"I have always been in the camp that fuel supplies eventually set crude prices, and with the latest builds in fuel supplies, the upside in crude is limited unless, of course, we see further tensions in the Middle East," Dennis Kissler, senior vice president at BOK Financial, said on Wednesday prior to the release.

On Wednesday, oil prices gave back earlier gains, falling more than 1% after EIA data showed a surprise crude build of 1.34 million barrels last week, versus expectations for a draw.

Ines Ferre is a senior business reporter for Yahoo Finance. Follow her on Twitter at @ines_ferre.

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