UPDATE 1-Elliott discloses 9.2 pct stake in Athenahealth, shares soar

(Adds details from filing)

May 18 (Reuters) - Activist investor Elliott Management disclosed a 9.2-percent stake in Athenahealth Inc on Thursday, citing "numerous" operational and strategic opportunities for the healthcare software provider to boost its shares.

Shares of Athenahealth, a $4.1-billion company based in Watertown, Mass., jumped 15.7 percent to $123 in premarket trading.

Elliott is a $33-billion multi-strategy hedge fund and an aggressive activist investor, launching more activist campaigns than any other hedge fund in the last few years.

The New York-based fund has broadened out its activism, from the technology sector to mining, retail, and healthcare.

The investment was disclosed in a securities filing and did not come with a letter from the fund, leaving Elliott's actual investment thesis and plan unclear for now.

Elliott's filing contained the standard language of a new activist campaign, saying the fund would seek to engage in a dialogue with Athenahealth's board regarding opportunities to increase shareholder value.

An Athenahealth spokeswoman was not immediately available for comment. (Additional reporting by Natalie Grover in Bengaluru; Editing by Sai Sachin Ravikumar and Nick Zieminski)