SAN FRANCISCO — Orrick, Herrington & Sutcliffe and Latham & Watkins are defending Violin Memory and a host of banks against a wave of securities litigation triggered by the company’s troubled IPO.

Latham partner Patrick Gibbs entered an appearance on Monday for J.P. Morgan Securities, Deutsche Bank Securities, Barclays Capital and Merrill Lynch, Pierce, Fenner & Smith, and other banks that underwrote the flash memory company’s IPO in September. Orrick partners James Kramer and Michael Torpey are representing Violin Memory and its officers.