Shares of Celsius Holdings fell after the energy-drink company reported lower profit and underwhelming revenue in the latest quarter.

The stock declined 18%, to $23.91, midday Thursday. Shares have lost about 48% of their value year to date.

The company before the bell posted a second-quarter profit of $55.3 million, or 14 cents a share, down from $99.9 million, or 33 cents a share, a year earlier.

Stripping out one-time items, earnings came in at 36 cents a share. Analysts polled by FactSet expected adjusted earnings of 42 cents a share.

Revenue climbed 11%, to $817.9 million, but missed the $870.1 million that Wall Street modeled.

Chief Executive John Fieldly said Celsius is taking steps to improve assortments and execution, vying to return its namesake brand to sustainable growth.

The Boca Raton, Fla., company's Celsius brand reported retail sales down 2% from last year, which it attributed primarily to optimization initiatives and a planned moderation in innovation activity. Rockstar energy sales decreased 13% from last year.

The declines were partially offset by Alani Nu retail sales, which increased 56%.

"We are confident the actions we are taking will strengthen the brand, and with a broader, more diversified portfolio, we believe we are well positioned to drive durable, long-term growth," Fieldly said.