One of the earliest backers of AquaBounty Technologies, the developer of genetically modified farmed salmon, sold down a massive holding in the company.

Investment group Third Security, an investment firm owned by billionaire Randal Kirk, sold just over 12 million shares in a secondary offering for $25.6 million (€22.8 million) in a deal that closed Tuesday.

Shares of the company, which trade on the NASDAQ, fell by sharply on Nov. 18 when the announcement that Kirk would be selling down his holdings.