US Markets

US stock futures add to gains after retail sales

U.S. stock-index futures furthered their modest advance on Tuesday after economic reports and ahead of U.S. Federal Reserve Chair Janet Yellen's testimony before Congress.

"So far the news has been pretty good," said Peter Cardillo, chief market economist at Rockwell Global Capital, citing earnings from the banking sector, Johnson & Johnson, along with data on June retail sales.

Separate economic reports had retail sales up 0.2 percent and import prices rising 0.1 percent in June.

Read MoreU.S. June retail sales up 0.2 percent versus 0.6 percent estimate

"The overall economic picture continues to brighten, with the consumer spending, albeit at a modest pace," said Cardillo.

Yellen's two-day appearance on Capitol Hill will provide an opportunity for investors to gauge the direction of monetary policy, particularly regarding when interest rates will start to rise.

"We do not expect to see a significant shift from her recent dovish tone," said Daiwa Capital's Emil Nicol in a research note.

"For example, we expect her to restate her assessment that there remains a significant degree of spare capacity in the labor market despite the steeper-than-expected decline in unemployment."

Third-quarter earnings were also in focus before the market open, following better-than-expected numbers from Citigroup on Monday. Yahoo and Intel will report after Wall Street closes.

Read MoreYahoo's earnings: It's all about the Alibaba purse

Goldman Sachs earnings easily beat analysts' expectations, coming in at $4.10 a share on revenue of $9.13 billion. It had been expected to earn $3.05 per share for the quarter, on revenue of $7.97 billion, off 7 percent from last year.

Read MoreGoldman Sachs earnings soar above estimates

JPMorgan Chase reported quarterly earnings and revenue that topped analysts' expectations. The company had been expected to earn $1.29 per share, off 19 percent from the same period last year.

Read MoreJPMorgan sees profit drop, still beats Wall Street

Johnson & Johnson also posted quarterly earnings and revenue that topped expectations, with shares of the diversified healthcare company rising in premarket trading.

Read MoreJ&J posts earnings of $1.66 a share versus $1.55 a share estimate