UPDATE 1-Kuwait pension fund says files lawsuit against UK's Man Group

(Adds Man Group response)

Jan 9 (Reuters) - Kuwait’s Public Institution for Social Security (PIFSS) said on Wednesday it had filed a lawsuit against UK asset manager Man Group Plc and its subsidiaries.

The pension fund is seeking $156 million in compensation relating to secret contracts between Man Group and a former PIFSS executive between 1996 to 2013, it said in a statement.

The lawsuit was filed with the UK’s Supreme Court, the fund said in the statement.

In a separate statement, Man Group said the subject matter of the PIFSS’s allegations dated back “over 20 years”.

“Based on the evidence we have seen to date, Man Group will dispute any claim and intends to vigorously and robustly defend any proceedings,” the company said. (Reporting by Hadeel Al Sayegh and Sinead Cruise; editing by Jason Neely and Ben Martin)