Exhibit 99.1

Willis Group Increases Stock Buyback Authorization and Declares Regular
Quarterly Dividend

    NEW YORK--(BUSINESS WIRE)--July 27, 2005--Willis Group Holdings
Limited (NYSE: WSH), the global insurance broker, today announced that
the Board of Directors approved an increase in the Company's existing
common share buyback authorization from USD300 million to USD500
million.
    The buyback is an open-ended plan to purchase, from time to time
in the open market or through negotiated trades with persons who are
not affiliates of the Company, shares of the Company's common stock.
    Separately, the Board of Directors declared a regular quarterly
cash dividend on the Company's common stock of USD0.215 per share, an
annual rate of USD0.86 per share. The dividend is payable on October
14, 2005 to shareholders of record on September 30, 2005.
    Willis Group Holdings Limited is a leading global insurance
broker, developing and delivering professional insurance, reinsurance,
risk management, financial and human resource consulting and actuarial
services to corporations, public entities and institutions around the
world. With over 300 offices in over 100 countries, its global team of
15,800 Associates serves clients in 180 countries. Additional
information on Willis may be found on its web site: www.willis.com.


    CONTACT: Willis Group Holdings Limited
             Investors:
             Kerry K. Calaiaro, +1 212-837-0880
             Email: kerry.calaiaro@willis.com
                 or
             Media:
             Dan Prince, +1 212-837-0806
             Email: daniel.prince@willis.com