Major U.S. stock indexes edged higher in midday trading as investors monitored Federal Reserve Chair Janet Yellen's remarks before Congress.

Strong earnings from Home Depot and positive developments in Greece's efforts to secure an extension of its financial rescue program also helped lift the market.

The Dow Jones industrial average rose 79 points, or 0.4 percent, to 18,196 as of 11:55 a.m. Eastern.

The Standard & Poor's 500 index added five points, or 0.3 percent, to 2,115. The Nasdaq composite gained a point to 4,962.

Home Depot rose 3 percent after beating earnings estimates, raising its dividend and announcing a share buyback.

Yellen said the central bank remains "patient" in deciding when to start raising interest rates. Most investors don't expect an increase in interest rates before June.