Amarin, the maker of the cholesterol-lowering medicine Vascepa, plunged the most in 16 months after investors lost confidence that the company will soon be acquired.

Amarin declined more than 20 per cent to $9.40 at one point before recovering slightly to close at $9. The Dublin-based company’s shares had gained 56 per cent in the 12 months to Thursday.

Investors had expected Amarin to sell itself or find a partner to market Vascepa, the company’s treatment for severely high levels of blood fats, or triglycerides, said Akiva Felt, an analyst for Wedbush Securities.

Instead, it announced on Thursday night that it had raised $100 million and started hiring a sales force for the medicine. The financing from Pharmakon Advisors and the start of a sales force may mean no sale is on horizon, he said.

“The concern is that this may be a signal a deal isn’t imminent,” Mr Felt said. “There had been expectations that there would be a strategic agreement in the near term.” – Bloomberg