Microsoft announced a second-quarter loss of $492 million on $18.06 billion in revenue. The software giant's first loss since the company joined the stock market in 1986 is the result of the acquisition of Acquantive. Microsoft bought this online advertising firm for $6.3 billion in 2007 to help in the online battle against Google, but the purchase failed to deliver the expected profits, and now the software giant writes down the value of Acquantive by $6.2 billion.
Microsoft is doing well in other areas, despite the decline in popularity of its Windows operating system, which dominated the personal computer market for years.
Revenue for the three months to June rose by 4% to $18.06bn.
Excluding the adjustment for the asset write-down, and the holding back of some income related to the launch of its Windows 8 system, Microsoft profits beat those expected by investors.
Shares were up 1.6% after the results were announced.
Microsoft says the update of the Windows systems is the most important redesign in more than 10 years.