UPDATE 1-Zenith National Q2 earnings lag Wall Street view

(Recasts, adds details, share movement)

July 22 (Reuters) - Workers' compensation insurer Zenith National Insurance Corp's (ZNT.N) second-quarter profit more than halved, missing analysts' estimates, due to a drop in underwriting income.

The Woodland Hills, California-based company said net income fell to $28.4 million, or 76 cents per share, from $65.3 million, or $1.75 per share, last year.

Net income includes net realized losses on investments after tax of $1.5 million, or 4 cents a share.

Analysts on average expected the company to earn $1.11, according to Reuters Estimates.

"Our underwriting income for the second quarter declined compared to the second quarter last year due to lower premiums and lower favorable loss reserve development," said Stanley Zax, chairman and president of Zenith National.

Net premiums earned fell 17 percent to $154.4 million from the year-ago quarter.

Underwriting income, before tax, from the workers' compensation segment fell 63 percent to $26.5 million.

Shares of the company, which have shed 18 percent so far this year, fell 5 percent to $34.96 in afternoon trade on the New York Stock Exchange. (Reporting by Amiteshwar Singh in Bangalore; Editing by Anil D'Silva)