NEW YORK - JPMorgan Chase reported a 7 percent drop in fourth-quarter earnings Wednesday, hit by more legal costs and a drop in trading revenue.

JPMorgan, the biggest US bank by assets, said it earned $4.93 billion, or $1.19 a share, for the three-month period ending in December. That compares with a profit of $5.28 billion, or $1.30 a share, a year ago.

JPMorgan's results were hit by a $990 million charge after taxes for legal expenses, more than analysts expected. The bank's results have been impacted by various legal costs over the last several quarters as it has settled lawsuits with state and federal regulators over its role in the housing bubble and subsequent financial crisis.

Total revenue fell 3 percent to $22.5 billion from $23.2 billion a year ago.

JPMorgan's investment banking division was hit by the sale of its commodities trading division and a slowdown in bond trading, one of the bank's larger businesses. Fixed-income revenue fell 23 percent from the prior year to $2.5 billion.

In the bank's commercial banking division, which includes credit cards, checking accounts, mortgages, and auto loans, there are signs that consumers are more willing to take on debt and are spending more.

Credit card balances were up 3 percent to $131 billion, while merchant processing volume, the amount of money being spent on the bank's credit and debit cards, was up 13 percent from a year ago. The bank processed 10.3 billion transactions in the quarter, up 7 percent from a year ago.

The bank also had an 8 percent increase from the prior year in auto loan originations.

The results missed Wall Street expectations. The average estimate of analysts surveyed by FactSet was for earnings of $1.31 a share.

JPMorgan shares fell 1.4 percent in pre-market trading to $58.