Insider Probe Is Spreading

Smith Barney, Harris Upham & Co. has become the second brokerage firm investigating possible involvement of California employees in the growing Business Week scandal.

The firm confirmed Tuesday that it is conducting an internal investigation of a California office amid reports that a sales assistant and a broker may have made trades similar to those of an active customer who had information about stock tips to be published in the magazine’s “Inside Wall Street” column.

The account of the customer in question has been suspended, a Smith Barney spokesman said. He would provide no further details.