* Q1 oper shr $1.16 vs est $1.07
* Announces $500 mln share buy back
* Net earned premiums up 4 pct
May 6 (Reuters) - Property and casualty insurer Allied World AWH.N posted a quarterly profit that beat estimates on higher earned premiums and announced a $500 million share buy back programme.
For the first quarter, the company earned $133.7 million, or $2.52 a share, compared with $131.4 million, or $2.57 a share, in the year-ago period.
The company reported operating income of $1.16 per share.
Analysts on average had expected the company to earn $1.07 a share, excluding items, according to Thomson Reuters I/B/E/S.
Net premiums earned rose 4 percent to $338.3 million.
Combined ratio, which is the percentage of premiums an insurer has to pay out in claims and expenses, was 99.5 percent.
The company said its board authorized a share repurchase programme of up to $500 million, effective through May 3, 2012.
Shares of the Bermuda-based company closed at $41.51 Thursday on the New York Stock Exchange. (Reporting by Jochelle Mendonca in Bangalore; Editing by Jarshad Kakkrakandy)