ZENITH NATIONAL INSURANCE CORP. 3,100,000 Shares Common Stock UNDERWRITING AGREEMENT dated July 27, 2004 Banc of America Securities LLC J.P. Morgan Securities Inc. Lehman Brothers Inc. Dowling & Partners Securities, L.L.C. Ferris, Baker Watts,...Zenith National • July 27th, 2004 • Zenith National Insurance Corp • Fire, marine & casualty insurance • New York
