WASHINGTON (Reuters) ? Aspen Insurance Holdings Ltd. said on Friday that it may periodically sell up to $500 million in ordinary and preference shares, depositary shares, debt securities, warrants, contracts and units.

Bermuda-based Aspen filed a shelf registration statement with the US Securities and Exchange Commission, which included another 53 million ordinary shares that may periodically be offered by selling shareholders.

It said it plans to use the proceeds for working capital, capital spending, acquisitions and other general corporate purposes.

Under a shelf registration, a company may sell securities in one or more separate offerings with the size, price and terms to be determined at the time of sale.

Aspen shares closed down 32 cents, or 1.3 percent, at $25.20 on the New York Stock Exchange.