UPDATE 1-Icahn acquires stake in Lawson Software

* Icahn reports 8.54 pct stake as of May 11

* Says stock is undervalued

* Wants to talk to discuss business with management

* Lawson shares rise 7.7 percent

BOSTON, May 24 (Reuters) - Activist shareholder Carl Icahn said he acquired an 8.54 stake in Lawson Software Inc as of May 11 and plans to discuss the company's business and operations with Lawson management.

The billionaire, who is now in a battle to take over Lions Gate Entertainment Corp , and is pushing for a seat on the board at biotechnology company Genzyme Corp, said in a regulatory filing that he purchased the Lawson stake because the shares were undervalued.

Lawson stock rose 7.7 percent on Monday.

Lawson spokesman Joe Thornton declined comment. Icahn could not be reached for comment.

Lawson makes specialty business management software used in an array of industries, from dairy farms to fashion houses. It had $757 million in revenue in its most recent fiscal year.

Shares in Lawson have climbed 50 percent over the past year, compared with a 31 percent gain in the Nasdaq Composite Index.

Lawson shares are priced at a premium to other software makers, based on earnings forecasts. They trade for about 16 times the average analyst forecast for next year's profit, excluding items, according to Thomson Reuters I/B/E/S, versus a forward P/E ratio of 12 for Oracle and 11 for Microsoft Corp.

Icahn has made billions investing in businesses that he believes are mismanaged or ripe for sale, then pushing the companies to improve their operations or sell themselves.

Shares in St. Paul, Minnesota-based Lawson rose 58 cents, or 7.7 percent, to $8.15 in heavy Nasdaq trade. (Reporting by Jim Finkle; editing by Carol Bishopric)