Changes headline, adds Emerson statement in paragraph 7

Feb 7 (Reuters) - Activist investor Elliott Management said on Friday it has invested more than $1.5 billion in Aspen Technology AZPN.O, opposing the company's decision to accept Emerson Electric's EMR.N $7.2 billion tender offer.

Elliott argues that Emerson's per-share offer of $265 for Aspen undervalues the company, adding that it will not tender its shares at the current price.

Aspen's shares rose about 3%, while those of Emerson fell 2%.

Emerson, which currently owns 57% of Aspen, agreed to buy the remaining shares in the software supplier that it did not own last month.

The St. Louis, Missouri-based industrial company is looking to strengthen its focus on the industrial automation segment through the acquisition.

Its offer price of $265 per share was at a premium of 10.4% to the $240 offer Emerson made in November.

"We remain confident in the benefits of the announced transaction with AspenTech, which was negotiated with and unanimously recommended by the independent AspenTech Special Committee," a spokesperson for Emerson said in a statement to Reuters.

Aspen did not immediately respond to a request for comment.

Elliott has become one of the most influential activist investors with about $70 billion in assets, having recently pushed for a breakup at Honeywell HON.O and changes at Southwest Airlines LUV.N.

The activist's $5 billion stake in Honeywell, its largest single investment, culminated in the company splitting its aerospace and automation businesses.

(Reporting by Utkarsh Shetti and Aatreyee Dasgupta in Bengaluru; Editing by Tasim Zahid and Alan Barona)

((UtkarshUmesh.Shetti@thomsonreuters.com))