Union Bank of California (NYSE:UB): 

WHAT: Keitaro Matsuda, senior economist for Union Bank of California,
      today released his December 2006 Economic Report focused on the
      California economy. The report titled, "California's Two Growth
      Engines -- One Stalls, the Other Keeps Going," is part of a
      monthly series produced by Union Bank of California on the
      California, Pacific Northwest and U.S. economies.

WHY:  The December 2006 Economic Report discusses factors affecting
      California's economic outlook, including:

      -- A historically low state unemployment rate
      -- The continued growth of service-sector jobs
      -- An overall decline in construction jobs
      -- Increased activity in industrial and multi-family 
         construction

WHO:  Keitaro Matsuda has served as senior economist for Union Bank of
      California since 1997. He monitors economic trends and
      developments for Union Bank management and customers. Mr.
      Matsuda is also a member of the economic advisory committee of
      the American Bankers Association. Union Bank of California, the
      wholly owned subsidiary of UnionBanCal Corporation (NYSE:UB),
      provides a broad range of financial services to consumers, small
      businesses, middle market and large corporations.

AVAILABILITY: The December 2006 Economic Report is available upon
              request.

INTERVIEW:    Keitaro Matsuda is available for interviews to share his
              insights about local, state and national economies, as
              well as year-end overviews and 2007 projections. Please
              contact Katie Pandes or Jessica Vitale to schedule an
              appointment.