Microsoft said on Tuesday it would bid 19 crowns per share for Norwegian Internet search software firm Fast Search & Transfer, valuing the company at about $1.2 billion.
"Fast's board of directors has unanimously recommended that its shareholders accept the offer," Microsoft said in a statement to the Oslo bourse.
Shareholders with 37 percent of Fast's stock, including its two biggest institutional investors -- Norway's Orkla and Hermes Focus Asset Management Europe -- have agreed to accept the offer which represents a 42 percent premium to its Jan. 4 closing price, it said.
The deal is subject to regulatory approval and acceptance from shareholders with more than 90 percent of Fast's shares, Microsoft said.
Goldman Sachs is acting as financial adviser to Microsoft, and Merrill Lynch is advising Fast, it said.
Fast shares rose 41.6 percent to 18.90 crowns at 0932 GMT, just below the bid level.
Fast will hold a telephone conference to discuss the offer at 1815 GMT (1315 New York time).