Arch Capital Group Ltd has reported net income of $427.8 million, or $1.05 per share, for the first quarter. That is up from $133.7 million for the same period a year ago.

After-tax operating income was $239.8 million, up from $189.8 million.

The Bermudian-based company's combined ratio improved to 90.7 per cent, from 91.5 per cent. Excluding catastrophic activity, the combined ratio was 81 per cent.

The first quarter results reflect a one-time gain of $74.5 million, or 18 cents per share, related to the purchase of a 29.5 per cent stake in Coface.

Arch's book value per common shares was $30.54 at the end of March, and improvement of 0.8 per cent since the end of 2020, and a 17 per cent increase year-on-year.

The company said that regulatory approvals are ongoing for the acquisition of Watford Holdings Ltd, and the transaction is expected to close this quarter.