NEW YORK (Reuters) - Chubb Corp, a property and casualty insurer, said first quarter earnings rose, buoyed by better results from its investments.

Excluding investment gains, earnings fell because of catastrophes in the Northeastern United States. But results excluding investment gains were still better than expected.

The Warren, New Jersey-based company's first quarter net income was $464 million, or $1.39 a share, compared with $341 million, or 95 cents a share in the same quarter last year.

Operating income, which excludes investment results, was $1.14 a share, above analyst estimates of 93 cents, according to Thomson Reuters.

The company realised $83 million of investment gains in the first quarter, compared with a loss of $173 million in the same quarter last year.