(Repeats to include Reuters Instrument Codes)
* Vice chairman sells 10 percent to Singapore's GIC
* Singapore fund now second biggest shareholder
* Straumann shares up 3.9 percent
ZURICH, Nov 26 (Reuters) - Straumann said major shareholder and vice chairman Thomas Straumann sold a 10 percent stake in the dental implant maker to Singapore's sovereign wealth fund, making it its second-biggest shareholder.
Thomas Straumann, a grandson of Reinhard Straumann who founded the company in 1954, said the "prevailing weak economic environment" had made it necessary to sell the stake to meet other financial commitments.
The sale means Singapore Investment Corporation (GIC) now holds 14 percent with Straumann's stake cut to 17 percent, the company said in a statement on Monday.
The value of the stake equates to roughly 150 million Swiss francs ($161.4 million), according to Thomson Reuters data.
"My belief in the long-term future of Straumann is undiminished, and I have every confidence in its business fundamentals, people and strategy," he said in the statement.
Shares in Straumann, which have shed more than a third of their value so far this year, were trading up 3.9 percent at 109.60 francs at 1245 GMT, compared with a 0.4 percent weaker European healthcare index.
The euro zone debt crisis has battered sales of dental implants made by Straumann and its Swiss rival Nobel Biocare as cash-strapped Europeans, worried about the downturn, cut back on non-essential dental treatment.
Last month Straumann announced a plan to cut roughly 6 percent of its workforce to improve margins as sales slow in Europe, its biggest market.
"We assume that Thomas Straumann sold his stake due to financial reasons and that it is not related to the company's operational performance," Vontobel analyst Carla Baenziger said in a note.
Straumann, who also chairs dental implant maker Medaris, has agreed to a one-year lock-up period during which he will not reduce his stake.
Swiss media reported earlier this year that Straumann had sold his luxury hotels in Basel and Gstaad to concentrate on his stakes in medical technology companies. ($1=0.9297 Swiss francs) (Reporting by Caroline Copley; Editing by Mike Nesbit)