A summary of Southern California-related business litigation developments during the past week.

Suit Against Saitama Bank: Robert Wang, a Los Angeles businessman and stockholder, filed suit in U.S. District Court against Saitama Bank Ltd., charging that the Japanese bank breached its fiduciary duty to stockholders by purchasing a major block of stock in a company at a significantly inflated price. The suit alleges that the bank violated securities laws in the United States and Japan by not disclosing that the stock purchased was of a company closely affiliated with the bank. Saitama Bank officials in Los Angeles had no comment on the suit.