US pre-open: Futures edge higher ahead of Yellen testimony and data dump

The Dow Jones Industrial Average is expected to open approximately 15 points higher, while the S&P 500 and the Nasdaq are set to begin the session up by two and 10 points respectively.

Yellen's testimony volatility

Yellen will give her semi-annual speech about the central bank’s economic outlook to the House Financial Services Committee at 15:00 BST, after the testimony is released publicly at 13:30 BST.

“Yellen is likely to face tough questions, many of which won’t be very relevant to the markets as these things can become quite political,” said Oanda’s senior market analyst Craig Erlam.

“But it’s under this scrutiny that monetary policy hints can, intentionally or not, be dropped. This can create quite volatile market conditions, especially when the comments come only a couple of months before the rate hike could come.”

A weak reading on June retail sales on Tuesday sparked speculation the Fed may delay its first rate hike, which pushed main stock averages higher for a fourth straight day.

Read more: "Don't hold your breath for an FOMC hike"

Away from Yellen’s speech, investors will be presented with a raft of economic data on Wednesday, starting with the Empire State manufacturing index for July, due out at 13:30 BST.

The producer index for June is released at the same time, followed by industrial production for last month and capacity utilisation at 14:15 BST and by the Fed’s beige book at 19:00 BST.

“Investors will be looking for firmer signs on whether an interest rate lift-off will occur in September, as well as details on the size of the USA’s second quarter recovery following its weak opening to 2015,” said Spreadex’s financial analyst Connor Campbell.

Earnings in focus

In company news, Bank of America rose 2.92% in pre-market trading after its second quarter earnings and revenue beat expectations.

BlackRock climbed 0.08% ahead of the bell after posting better-than-expected second quarter earnings and revenue.

Biotech group Celgene jumped 5.83% in pre-market trading after announcing late on Tuesday that it was in talk to buy Receptos, whose shares surged 10.5%.

Delta Air Lines rose 2.61% after its quarterly revenue and earnings beat Wall Street's estimates.

Netflix and Intel will report after the closing bell.

Elsewhere, European stocks fluctuated as investors waited for Greece’s parliament to vote on the bailout deal, while Asian markets closed on a mixed note, with Chinese stocks ending low, despite solid economic data.

The dollar climbed 0.16% against the yen but was broadly flat against both the pound and the euro, while gold futures were flat at $1,153.50.

Oil prices edged lower, with West Texas Intermediate shedding 0.46% to $52.80 a barrel, while Brent lost 0.62% to $58.15 a barrel.