Bermuda-based re/insurer Aspen Insurance Holdings Ltd. has capitalised on its low stock market valuation to buy back $200 million of its own shares.

Meanwhile, Bermuda competitor Allied World Assurance Company Ltd. announced it is selling $300 million of debt, partly to buy back its own shares.

Aspen announced on Wednesday that it had launched an accelerated share repurchase programme with Barclays Capital to buy back $184 million of its ordinary shares.

This is in addition to $16 million of open market share repurchases undertaken since September 30, 2010.

Under Aspen's accelerated share repurchase programme "a substantial majority" of the shares bought back will be received and cancelled within the current quarter.

Yesterday, Aspen's share price was up 78 cents, or 2.7 percent, in afternoon trading, at $29.84.

Like many of its property and casualty insurance industry peers, Aspen is trading substantially below book value. Aspen's diluted book value per share at September 30 was $38.22.

Buying back shares adds to book value per share.

Aspen chief financial officer Richard Houghton said: "We are committed to active capital management, in particular returning surplus capital to shareholders as efficiently as possible.

"Our current valuation levels presented an attractive opportunity to buy back $200 million of our shares through a combination of an accelerated share repurchase programme and open market purchases."

Following completion of the accelerated share repurchase programme, the company will have another $192 million of authority, given by the company's board in February this year, for share repurchases. Aspen said the purchase will be funded with cash on hand and the sale of investment assets. The ordinary shares will be retired once purchased.

Based on Aspen's closing share price on Wednesday, the accelerated share repurchase program and the completed open market share repurchases together represent approximately nine percent of Aspen's total market capitalisation.

Allied World said the 10-year senior notes it is selling would carry a 5.5 percent interest rate and were priced to yield 5.56 percent.

Net proceeds from the offering, which is expected to close next Monday, will be used for general corporate purposes, including the repurchase of common shares.