NEW YORK ( TheStreet) -- Property and casualty insurer NYMagic ( NYM) has agreed to be acquired by property and casualty company ProSight Specialty Insurances for $25.75 a share in cash, which represents a 23.5% premium to NYMagic's closing price on Wednesday.

The deal is expected to close in the fourth quarter, with Goldman Sachs acting as a financial advisor to NYMagic for the deal.

Shares of NYMagic closed down 4.1% to $20.85 Wednesday. In Thursday morning trading, NY Magic stock was trading up 21.4% at $25.31, slightly below the ProSight purchase price.

-- Reported by Andrea Tse in New York

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