Trading remained muted as investors continued to focus on the manhunt for a suspect in the Boston Marathon bombings. The markets traded mixed during the midday with the Dow slipping 17 points to 14,519 while Nasdaq climbed 36 points to 3202.

On the upside

SeaWorld Entertainment (NYSE: SEAS) surged on its first trading day.

Shares of Blackhawk Network Holdings (Nasdaq: HAWK) soared in its market debut.

Celanese (NYSE: CE) reported better than expected first quarter earnings.

On the downside

First quarter earnings plunged for Acacia Research (Nasdaq: ACTG) as revenue dropped.

Rambus (Nasdaq: RMBS) reported a wider than expected loss for the first quarter.

UBS downgraded Magnum Hunter (NYSE: MHR) from a Buy rating to a Neutral rating.

In the broad market, advancing issues outpaced decliners by a margin of nearly 7 to 3 on the NYSE and by 2 to 1 on Nasdaq. The broader S&P 500 index gained 10 points to 1552.