NEW YORK (Reuters) - Bermuda-based bond insurer Assured Guaranty Ltd. said its proposed acquisition of Belgian lender Dexia's troubled US bond insurance unit cleared an antitrust hurdle.

Assured said the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act had expired on Tuesday.

The company said it expects to hold a special general meeting of its shareholders to vote upon the merger in March.

Billionaire investor Wilbur Ross, who has a key stake in Assured, had expected the US antitrust regulators to make a decision on the deal by the end of January or February.

In November, Dexia, the world's largest municipal lender and the recipient of a 6.4 billion euro ($8 billion) public bailout in September, said it would sell the insurance business of Financial Security Assurance (FSA) to peer Assured Guaranty.

Assured, which has largely avoided the credit problems that have plagued rivals Ambac and MBIA by a lower exposure to repackaged sub-prime mortgages, expects the deal to be completed by the end of the first quarter of 2009.

Shares of Assured closed at $8.09 on Tuesday on the New York Stock Exchange. The stock has lost 15 percent of its value since Dexia announced the sale on November 14.