Timeline: Microsoft tries to buy Yahoo

A chronology of events surrounding Microsoft’s efforts to acquire Web search and advertising competitor Yahoo.
1975: Microsoft co-founded by 19-year-old Harvard dropout Bill Gates and former Seattle school pal Paul Allen.
1986: Microsoft goes public at $21 per share (prior to many stock splits).
1994: Yahoo founded by David Filo and Jerry Yang, engineering Ph.D. candidates at Stanford University.
1996: Yahoo goes public in highly successful IPO.
1997: Microsoft acquires Hotmail, a free Web-based e-mail service.
1998: Google founded.
2001: Laid low by the tech crash, Yahoo brings in Hollywood dealmaker Terry Semel as CEO.
2004: Google holds initial public offering.
June 2006: Gates says he will transition out of a day-to-day role at Microsoft as of July 2008.
October 2006: Google announces plan to buy YouTube for $1.65 billion, giving it a highly popular video-sharing site on which to sell more ads.
April 2007: Google agrees to pay $3.1 billion in cash to acquire ad-management technology company DoubleClick Inc.
May 2007: Microsoft announces it is buying online advertising company aQuantive for $6 billion, its biggest acquisition ever.
June 2007: Semel steps down as Yahoo's CEO; co-founder Jerry Yang takes over.
Jan. 31, 2008: Yahoo announces Semel has resigned as chairman, effective immediately.
Feb. 1: After two years of talks and speculation, Microsoft makes unsolicited offer to buy Yahoo for $31 per share, or $44.6 billion.
Feb. 11: Yahoo rejects Microsoft’s offer, saying it “substantially undervalues” the company’s brand and worldwide assets.
Feb. 19: Gates tells The Associated Press the software maker isn’t in talks with Yahoo about raising its offer.
March 5: Yahoo extends a deadline for nominating candidates to its board, buying time to strike an alternative deal. Yahoo is said to be in talks with Google Inc., News Corp.’s MySpace.com and Time Warner Inc.’s AOL.
March 18: Yahoo releases optimistic revenue forecast for next two years to justify rejecting bid.
April 5: Microsoft CEO Steve Ballmer gives Yahoo three weeks to agree on a buyout or expect the software maker to go hostile — and potentially lower the offer price.
April 9: Yahoo says it will try using Google’s search ad engine instead of its own in a limited test. Microsoft’s general counsel, Brad Smith, raises antitrust concerns.
April 26: Microsoft deadline for Yahoo to accept the offer expires. Both companies remain silent.
May 1: Ballmer tells Microsoft employees that he “won’t go a dime above” what he thinks Yahoo is worth, and that he is willing to walk away from the deal.
May 3: Microsoft withdraws its offer after raising its bid by $5 billion to $33 per share. Yang demands at least $37 per share, an additional $5 billion.
May 8: Billionaire investor Carl Icahn announces he has acquired a 4 percent stake in Yahoo and launches an effort to oust the company's board and revive talks with Microsoft.
Sources: Associated Press, msnbc.com research