The firm did not say how long the repurchase scheme would last. Its previous buyback, also worth $40bn, was announced in September 2013 and is due to be completed by the end of the year.

Share buybacks tend to support a company's share price and are popular with investors.

Microsoft also announced that it was raising its quarterly dividend by 8%, to 39 cents a share.

Microsoft shares rose 1% in after-hours trading.

Big deal

Earlier this year Microsoft announced its biggest ever acquisition - the purchase of the professional networking website LinkedIn - for just over $26bn (£18bn) in cash.

That was considered a high price for LinkedIn, which reported an annual loss of $166m.

Microsoft chief executive Satya Nadella said it was part of Microsoft's transformation into a cloud computing business, providing a range of professional services to clients - including a social network to connect them to each other.

(BBC)