50.5 percent from 52.7 percent a year earlier, hurt by the promotional and operational costs. Promotion spending rose 23 percent.
Net sales increased 14.2 percent to $541.9 million, but this lagged analyst estimates of $578.5 million.
Sales in the quarter were partly hurt by a drop in Canada due to inventory adjustments made by distributor Coca-Cola Refreshments Canada, Monster said.
A stronger U.S. dollar had a negative impact of $12 million on sales and lower sales of its Monster Energy Extra Strength drink also hurt revenue, Sacks said. All other energy drinks posted higher sales, he added.
Sales of energy drinks form the fastest growing segment of the soft drinks market. Sales rose 17 percent to $9 billion in 2011 and are expected to exceed $10 billion this year, according to Beverage Digest.
Shares of the company closed at $44.97 on the Nasdaq on Wednesday.