The board of directors of Worcester-based The Hanover Insurance Group Inc. has authorized a $100 million increase to the company’s existing share repurchase program.

The program initially was authorized by the board in October 2007 and increased in size in September, allowing for the repurchase of up to $200 million of the company’s outstanding common stock, according to a statement.

This most recent increase will provide for aggregate repurchases under the program of up to $300 million of the company’s common stock. As of Dec. 7, the company had utilized approximately $108 million of this authorization, according to a statement.

The company also announced it has used a portion of this authorization to effect the immediate repurchase of 2.4 million shares of the company’s common stock at a price per share of approximately $41.34, for a total purchase price of approximately $100.6 million.