By Joseph Woelfel, TheStreet.com

Yammer agreed to sell itself to Microsoft (MSFT) for $1.2 billion, The Wall Street Journal reported, citing a person familiar with the matter. It's unclear when the acquisition of Yammer, the business-software company, will be completed and announced, said a person familiar with the deal, the Journal reported. Yammer is often called Facebook for the workplace because it creates private social networks inside companies, the newspaper noted.
(Microsoft owns and publishes Top Stocks, an MSN Money site.)

Dell (DELL) is the "strategic bidder" that offered to buy Quest Software (QSFT) for $2.15 billion in cash, sources familiar with the matter told Reuters. PC maker Dell is the unidentified company mentioned in a statement made by Quest, which disclosed on Thursday that it had received an offer from a "strategic bidder" of $25.50 a share, Reuters said. The reported Dell bid tops an earlier offer of nearly $2 billion from private investment firm Insight Venture Partners. Shares of Quest Software gained more than 9% Thursday to finish at $26.06.

United Technologies (UTX) received conditional approval from China for its $16.5 billion takeover of Goodrich (GR), the maker of aircraft parts. Goodrich will be forced to divest its electrical power generation and transmission systems businesses and should sell 60% of joint venture Aerolec within six months, said China's Commerce Ministry.

Best Buy (BBY) shares rose more than 2% Thursday following an upgrade by Citigroup.

Citigroup changed its rating on the consumer electronics retailer to neutral from sell. Best Buy shares are down 35% this year.

Seagate Technology (STX) said Thursday it reached a deal to acquire a controlling interest in storage device maker LaCie.

The Federal Reserve said that the U.S. government bailout funding that went to American International Group (AIG) has been repaid, according to Bloomberg. Shares of AIG ticked up 12 cents, or 0.39%, to $31.15 in premarket trading Friday.