Legal battle over U.S. 'volatility' product expands to 2nd company

NEW YORK, March 15 (Reuters) - The legal fight over a complex Credit Suisse financial instrument betting on stock market swings is expanding, with a new lawsuit targeting one of the product's service providers.

An investor on Thursday sued the bank and a unit of Janus Henderson Group PLC over their VelocityShares Daily Inverse VIX Short-Term Exchange-Traded Note, which lost most of its value after the U.S. stock market closed one day last month.

Both companies have denied wrongdoing. (Reporting by Trevor Hunnicutt Additional reporting by Jonathan Stempel; Editing by Tom Brown)