Goldman Sachs had a strong first quarter, with net earnings of $5.63 billion, or $17.55 per share, and net revenue of $17.23 billion. These results beat analyst expectations for both revenue and profit. Still, the stock dropped 4.5% in premarket trading on Monday, showing that investors are looking closely at the mixed results behind the headline numbers.

The strongest results were in investment banking and equities trading. Investment banking fees jumped 48% from last year to $2.84 billion, thanks to more advisory work on mergers and acquisitions and higher equity and debt underwriting. Goldman’s equities trading desk had a record quarter, with equities financing, which means lending to hedge funds and other big clients for their trades, rising 59% to a new high. Instead of hurting results, the volatile markets in the first quarter actually helped boost Goldman’s trading revenue.

The fixed income, currencies, and commodities division weighed on overall performance. Although there were gains in commodity and currency revenue, the FICC business fell 10% year over year due to lower income from interest rate, mortgage, and credit products. This decline in FICC income offset gains from other divisions, raising concerns among investors about the sustainability of Goldman’s earnings growth. Energy markets were especially volatile, helping some trading desks but hurting others. Many analysts pointed to the FICC decline as the main weak spot in an otherwise strong quarter, contributing to investor caution despite strong headline results.

Wider sector trends also contributed to Goldman’s stock drop. The KBW Nasdaq Bank Index fell 6% in the first quarter, reflecting challenges for bank stocks amid geopolitical uncertainty and market swings. Goldman’s shares were down 0.7% for the year through Friday, mirroring the S&P 500’s 0.6% drop. The premarket selloff suggests the market is now weighing the sustainability of trading revenue and whether FICC weakness is a temporary issue.