Worcester-based Hanover Insurance Group Inc. posted a better-than-expected first-quarter profit, helped by a surge in income from personal lines and investment gains.

The insurance holding company posted a quarterly net income of $41.8 million, or 87 cents a share, compared with $25.8 million, or 50 cents a share, a year ago.

Analysts on average had expected a profit of 52 cents a share, according to Thomson Reuters I/B/E/S.

Personal lines pretax segment income for the quarter jumped to $34.5 million from $3.1 million, while commercial lines income fell to $22.8 million from $47.6 million.

Investment gains reversed to a profit of $10.2 million, compared with a loss of $6.2 million last year.

Shares of the company closed at $43.35 Thursday on the New York Stock Exchange.