Hennessy Advisors Inc. (NASDAQ: HNNA) plans to acquire management of about $640 million in mutual funds from a Milwaukee-based firm.

Hennessy signed a definitive agreement with Westport Advisers LLC to purchase the assets related to the management of The Westport Funds, which are the Westport Fund and the Westport Select Cap Fund, the Novato-based company announced May 2. Upon completion of the transaction, the assets related to the Westport Fund and the Westport Select Cap Fund will merge into the Hennessy Cornerstone Mid Cap 30 Fund, with shareholders of the Westport Funds becoming shareholders of the Hennessy Cornerstone Mid Cap 30 Fund.

The deal, expected to be completed in the third quarter after regulatory and stakeholder approval, would bring total assets managed by Hennessy Advisors to more than $7 billion, the company said.

“We strive to deliver strong investment management and performance, quality customer service and a high standard of business ethics to our shareholders, and we are very proud of our track record in each of these areas,” said Neil Hennessy, Chairman, CEO and president of Hennessy Advisors (hennessyadvisors.com).

Andrew Knuth, co-founder of Westport Advisers and chairman of Westport Asset Management, said Hennessy is committed to the mutual fund business and has a solid reputation in the asset management.