* Clariant CEO vows to remain despite defeat
* White Tale boosted stake to more than 20 pct
* Clarient shares down 1.7 percent (Adds comment from Clariant CEO, details of investor activism)
ZURICH, Oct 27 (Reuters) - Swiss specialty chemicals maker Clariant and U.S. group Huntsman abandoned their $20 billion merger on Friday, notching a win for activist investors who fought against the deal for months on the grounds it would destroy shareholder value.
White Tale, the investment vehicle of hedge fund manager Keith Meister and New York City-based fund 40 North, had increased its Clariant stake to more than 20 percent, Reuters reported on Thursday ahead of the announcement of the tie-up being dropped.
White Tale's rising stake, coupled with other Clariant shareholders who came out against the deal, left the Swiss company doubtful of mustering the two-thirds support necessary for the merger to go through.
The successful revolt comes amid a wave of investor activism in Switzerland, where Credit Suisse is under attack and Nestle also faces demands for change.
Chief Executive Hariolf Kottmann said Clariant still had options to explore after further talks with White Tale.
"To do a merger of equals ... is one option, to make a large transformational transaction is another option, to continue to stand alone is a third option," Kottmann told reporters on a call where he vowed to remain CEO.
"There are four or five of these options, and they have all pros and cons."
Clariant shares pared early losses to trade down 1.7 percent by 0706 GMT.
Skepticism that the deal would happen had been mounting as even supporters sold down their stakes.
Clariant trades at a multiple of 18.7 times forecast earnings, a discount to the average 21.3 ratio of peers in the chemicals industry, according to Starmine data.
Clariant and Huntsman, which said on Friday its third-quarter costs linked to the merger were $18 million, agreed to forego breakup fees. Huntsman CEO Peter Huntsman said separately he was disappointed the transaction did not go through.
Clariant and Huntsman in May struck the pact that would have given Clariant 52 percent of the combined entity, saying the combination would produce around $400 million in annual cost synergies and create the world's second-biggest specialty chemicals maker behind Germany's Evonik.
But Meister and 40 North's David Winter and David Millstone contended the merger would not deliver enough benefits, while exposing Clariant to Huntsman's debt as well as the U.S. company's volatile commodity chemicals business.
"It both significantly destroys existing Clariant shareholder value and prevents Clariant from pursuing multiple alternative and immediate opportunities to unlock value for its shareholders," White Tale said last month.
White Tale did not immediately make a statement on Friday.
Kottmann said: "We are in talks ... with White Tale and we will carefully listen what their expectations are, then we will discuss this internally, and then we will come forward with a decision." (Editing by Michael Shields and David Holmes)