Chicago-based Old Republic International Corp. has announced its intent to acquire PMA Capital Corp. of Blue Bell, Pa., for $365 million, pending all approvals.

Old Republic, an insurance holding company, said in a statement it will acquire all of PMA’s outstanding stock in a deal approved by the boards of directors of both companies. The deal consists of $228 million for PMA common shares and $137 million for its debt.

The transaction is expected to close during the third quarter, subject to approval by PMA shareholders, regulators and other customary closing conditions, the companies said.

PMA Capital Corp. is the holding company for PMA Cos., a provider of workers’ compensation and related commercial insurance risk management solutions to clients nationwide. PMA Cos. consists of The PMA Insurance Group, as well as fee-based businesses, PMA Management Corp., PMA Management Corp. of New England and Midlands Management Corp.

Vincent Donnelly, president and chief executive officer for PMA, said following the closing, the firm will continue operations as PMA Cos., with its headquarters in Blue Bell, as well as its current leadership team and local service locations.

“We believe that this merger will have positive benefits to our shareholders, clients and employees,” Donnelly said in a statement. “We expect that this transaction will enable our shareholders to realize greater long-term value than if we continued to operate as a stand-alone entity. We also believe that the additional financial strength and stability of a larger well-diversified company will benefit our clients, employees and other stakeholders.”

Donnelly added that PMA is “excited about the opportunity that Old Republic presents for the continued profitable growth of our businesses.”

Al Zucaro, chairman and CEO for Old Republic, said his company is “extremely pleased” to welcome PMA management and associates to its family of companies.

Old Republic’s subsidiaries market, underwrite and provide risk management services for a wide variety of coverages, principally in the property and liability, mortgage guaranty, and title insurance fields. One of the nation’s largest publicly held insurance organizations, Old Republic has assets of about $14.3 billion and common shareholders’ equity of nearly $4.0 billion, the firm said.

“This merger is consistent with our long term strategic plan to grow our general insurance business,” Zucaro said. “The alliance of our two companies results in a well-capitalized insurance group appropriately positioned to take advantage of the many opportunities and synergies which will no doubt be available to us. The two companies share a commitment to conservative underwriting and a focus on select industries important to the American economy.”

He added that Old Republic is “convinced” the merger “will at once provide greater scale, balance and diversification for our general insurance business, and produce enhanced future benefits for the combined shareholder groups.”