U.S. billionaire Len Blavatnik is planning to file a lawsuit against JPMorgan Chase on Monday, accusing the bank of mismanaging an investment account that held $1 billion in assets owned by Blavatnik's industrial holding company, Access Industries, the New York Times said.

In the proposed lawsuit, Blavatnik's lawyers blame Ted Ufferfilge, a JPMorgan banker advising Access, for losing $98 million of the company's money betting on risky subprime mortgage securities, according to the paper.

The proposed lawsuit contends that Ufferfilge told Access that its funds were being invested in conservative instruments, not securities that wound up at the center of the American mortgage crisis, the paper said, citing a draft of the complaint prepared by the law firm Quinn Emanuel Urquhart Oliver & Hedges.

An Access spokesman told the paper that JPMorgan bought the subprime securities for Access at a time when the bank itself was unwinding its positions in similar investments.

JPMorgan intends to defend this matter vigorously, a spokeswoman for the bank told the paper. We believe this lawsuit is meritless and a transparent attempt to recover losses resulting from the unprecedented market downturn, she told the paper.

The bank has hired the law firm Paul, Weiss, Rifkind, Wharton & Garrison to represent it in the case, the paper added. JPMorgan and Access Industries could not be immediately reached for comment by Reuters.

(Reporting by Chakradhar Adusumilli in Bangalore; Editing by Muralikumar Anantharaman)