Oil tumbled to a seven-month low on speculation that U.S. crude stockpiles climbed to the highest level since 1990 and as the euro weakened on concern that the debt crisis will overwhelm Spain.

New York futures fell as much as 3.6 percent and Brent oil traded in London dropped below $104 a barrel for the first time this year. An Energy Department report tomorrow is projected to show that U.S. supplies rose 1 million barrels to 383.5 million last week, according to analysts surveyed by Bloomberg. The euro fell versus the dollar as Spain’s default risk increased.

The drop in prices accelerated after a report showed the number of Americans signing contracts to buy previously owned homes fell in April by the most in a year. The index of pending home resales dropped 5.5 percent following a revised 3.8 percent gain the prior month, figures from the National Association of Realtors showed today in Washington.

Oil for July delivery on the New York Mercantile Exchange reached $87.49, the lowest intraday level since Oct. 24. Prices are down 16 percent this month, the biggest drop since December 2008.

Brent oil for July settlement declined $2.94, or 2.8 percent, to $103.74 a barrel on the London-based ICE Futures Europe exchange. The contract touched $103.23, the lowest level since Dec. 19.