SAN FRANCISCO (AP) _ Union Bank of California disclosed plans today to shed 1,400 workers, or 15 percent of its work force, in an effort to boost profits and expand other parts of its business.

Most of the layoffs will be in southern California, although about 100 to 200 will be in the San Francisco Bay area. Employees will get four weeks to a year of severance pay, depending on seniority.

UnionBanCal Corp., the bank's San Francisco-based parent, said the layoffs will boost pre-tax profits by $135 million. Net earnings will rise another $90 million through increased fees.

Union Bank shares were up less than 1 percent in morning trading today, rising 25 cents at $38 a share on the New York Stock Exchange.

The company said the changes will allow the bank to expand its ATM network, open a new branch, add telephone customer service clerks and improve Internet banking.

The company has had a reputation for benevolence toward employees. When it was created with the combination of Union Bank and Bank of California four years ago, it avoided the mass layoffs typical of bank mergers.

But last year, the ailing Bank of Tokyo-Mitsubishi, which owns 64 percent of Union Bank, sold stock to American institutional investors who demanded a better return on their investments.

Union Bank has 241 offices in California, and six in Oregon and Washington. It had $32.4 billion in assets as of June 30.