Microsoft is taking a $6.2 billion (£3.95 billion) goodwill charge this quarter to recognise that its online services business won't grow as quickly as it had forecast.
Microsoft bought aQuantive in 2007 for just over $6.3 billion to improve its online advertising business. At the time it was Microsoft's biggest deal ever, though it has since bought Skype for $8.5 billion.
In an acquisition, goodwill reflects the value of intangible assets that can contribute to future growth, such as a strong brand or good customer relations. The write-down shows that Microsoft no longer values the aQuantive assets as highly.
"While the aQuantive acquisition continues to provide tools for Microsoft's online advertising efforts, the acquisition did not accelerate growth to the degree anticipated, contributing to the write down," Microsoft said.
Parts of its online services business have been doing better, Microsoft noted. Bing's search share in the US has been expanding and revenue per search growing, it said.
"While the Online Services Division business has been improving, the company's expectations for future growth and profitability are lower than previous estimates," Microsoft said in a statement.
It said the non-cash write-down would not affect its "ongoing business or financial performance."
Read what we said in 2007: Microsoft £3bn aQuantive deal is no silver bullet