Transatlantic Holdings Inc. (NYSE: TRH) shares rose 5.6% to $47.75, a day after National Indemnity Co., a unit of Warren Buffett’s Berkshire Hathaway Inc. (NYSE: BRK.A) offered $3.2 billion to acquire the reinsurer. Volume for Transatlantic numbered 1.4 million shares, compared to a daily average of about 790,000.

A news release out Sunday, August 7 noted that Transatlantic confirmed it had received a proposal from National Indemnity to acquire all of Transatlantic’s outstanding shares of common stock for $52.00 per share.

The release quoted a letter to Transatlantic CEO Robert Orlich from National Indemnity CEO Ajit Jain as saying “With your stock trading at $45.83, I have to believe that you will find our offer to buy all of Transatlantic shares outstanding at $52.00 per share to be an attractive offer… Should you decide to accept this offer, your agreement that should the deal not close for any reasons that are under your control by December 31, 2011, a break-up fee of $75.0 million would be paid to us.”

Transatlantic Holdings, Inc. is a leading international reinsurance organization headquartered in New York, with operations on six continents. Its subsidiaries, Transatlantic Reinsurance Company®, Trans Re Zurich Reinsurance Company Ltd. and Putnam Reinsurance Company, offer reinsurance capacity on both a treaty and facultative basis ― structuring programs for a full range of property and casualty products, with an emphasis on specialty risks.