UPDATE 1-3i to cut headcount by 15 pct

(adds detail from statement)

LONDON, Dec 4 (Reuters) - Private equity firm 3i Group Plc (III.L) said on Thursday it is to reduce its headcount by about 15 percent in response to toughening market conditions.

"Although these decisions are clearly difficult for those affected, the outlook for markets is challenging," said chief executive Philip Yea.

3i said the decision to reduce its worldwide staffing levels by approximately 100 positions followed a thorough review and were designed to reduce costs and position the group for market opportunities. (reporting by Simon Meads; Editing by Hans Peters)