WASHINGTON (Reuters) - U.S. antitrust authorities said on Tuesday they have approved IBM Corp's purchase of software maker Cognos Inc for $5 billion.

IBM's proposal to buy Canada-based Cognos, the last major independent maker of business intelligence software, was on a list of approved deals that the Federal Trade Commission releases periodically.

Cognos makes software that combs through vast amounts of data to analyze business trends. For example, Harrah's Entertainment Inc uses a Cognos program to keep frequent gamblers coming back to its casinos.

Software is IBM's fastest-growing and most profitable division. IBM also uses software products to get customers to buy its consulting services and hardware.

IBM said last month it had signed an agreement to buy Cognos for $58 a share.

Oracle , SAP and now IBM are investing in business intelligence software to boost their product portfolios. Such programs work with databases sold by Oracle and IBM, as well as business management software from SAP and Oracle.

Cognos, based in Ottawa, has about 4,000 employees and more than 25,000 customers.

(Reporting by Diane Bartz; editing by Tim Dobbyn)
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