Hotel Chocolat has agreed to a £534m takeover offer from Mars, the maker of goods from Snickers bars to Pedigree dog food.
The UK specialist chocolatier retailer said the cash offer represented a 170% premium to its London share price of 139p.
Shares soared by 164% at the market open in response.
Mars has proposed to pay 375p for each Hotel Chocolat share under the terms.
As an alternative, investors can elect to secure a share in the bid company for each Hotel Chocolat share they already own.
The board has recommended the deal.
The company, which has a 20-year history but just seven as a London-listed firm, said it would allow its brand to expand, particularly internationally.
Hotel Chocolat, so-named due to its hotel on a cacao estate in Saint Lucia, currently has 130 stores and a partnership in Japan but lacks the substantial funds needed to make a big push overseas.
Chief executive and joint founder Angus Thirwell, who will stay with the business under the terms of the deal with Mars, said: “We know our brand resonates with consumers overseas, but operational supply chain challenges have held us back.
“By partnering with Mars, we can grow our international presence much more quickly.”
He and co-founder Peter Harris both own 27% of the equity, according to LSEG data.