Stock futures were largely flat on Wednesday morning as investors overcame jitters tied to a terrorist attack in Brussels a day earlier. 

S&P 500 futures were up 0.01%, Dow Jones Industrial Average futures declined 0.02%, and Nasdaq futures slid just 0.01%.

The death toll in the two explosions in Brussels has risen to 34, according to security officials, while several hundred more are injured. Brothers Khalid and Brahim el-Bakraoui have been named as the suicide bombers, while third suspect Najim Laachraoui was reported to have been captured by police overnight. However, the latest reports said a man arrested earlier Wednesday wasn't the third suspect. The three are suspected of being involved with the ISIS group responsible for terror attacks in Paris in November. 

The terrorist attacks at Belgian transport hubs reignited global terrorism concerns Tuesday, leaving U.S. markets drifting around Tuesday's closing levels. The S&P 500 ended the day down 0.09%, the Dow slid 0.23%, and the Nasdaq gained 0.27%.

Crude oil was lower on Wednesday, though was holding above the psychologically important $40 level. Traders have been recently concerned over global oversupply, though hopes of a production freeze among Organization of Petroleum Exporting Countries has eased worries somewhat. West Texas Intermediate crude oil was down 1% to $41.06 a barrel on Wednesday morning. 

Merck(MRK) - Get Report jumped more than 2% in premarket trading after a federal jury in California ruled in its favor in a lawsuit against rival Gilead Sciences(GILD) - Get Report over several key hepatitis C patents. Merck accused Gilead of infringing on patents it filed over a decade ago, claiming Gilead's sofosbuvir infringes on those patents. Merck is seeking billions in damages and royalties on sales of Gilead's two hepatitis drugs. 

Pinnacle Foods (PF) dropped in premarket trading after current CEO Robert Gamgort announced he will leave the company at the end of April. Keurig Green Mountain (GMCR) announced that Gamgort will assume the position of CEO at its company. 

General Mills(GIS) - Get Report was lower after a mixed quarter, dragged on by weakness overseas. The packaged food company earned an adjusted 65 cents a share, 3 cents above estimates. Sales fell to $4 billion, falling short of estimates of $4.08 billion.

Krispy Kreme (KKD) fell more than 3% in premarket trading after issuing a weaker-than-expected outlook. The company anticipates fiscal 2017 earnings between 87 cents and 91 cents a share, short average consensus of 92 cents. The doughnut chain also increased its stock buyback program by $100 million. 

Red Hat(RHT) - Get Report fell 3% despite a better-than-expected quarter and above-consensus outlook. The tech company reported fourth-quarter earnings of 52 cents a share, beating estimates by a nickel, while sales jumped 17%. First-quarter earnings of 50 cents a share were in-line with forecasts. 

Nike(NKE) - Get Report was lower before the bell following a mixed third quarter. The athletic apparel company reported earnings of 55 cents a share, 6 cents above forecasts, flat margins from a year earlier, and sales of $8.03 billion, missing estimates by nearly $200 million. Higher margins were due to increased warehouse costs, a stronger dollar, and excess inventory.