Nassau Re has completed its purchase of The Phoenix Cos., founded by Hartford civic, religious and business leaders in 1851 as the American Temperance Life Insurance Co.

The Phoenix was a mutual insurer for most of its history, and became a publicly traded company 15 years ago. With Monday’s closing, Phoenix is now a privately held, wholly owned subsidiary of Nassau Re.

Phoenix will continue to be headquartered in Hartford, with another office for the life insurance division in East Greenbush, N.Y. The company has about 650 employees, with 360 in Hartford. The Phoenix owns the downtown “Boat Building,” a 52-year-old Hartford landmark.

Nassau Re put $100 million of new equity capital into Phoenix, as well as $80 million of reinsurance assets to support PHL Variable Insurance Co. Its new owner said the cash infusion should accelerate the company’s turnaround. 

Nassau Reinsurance was launched in New York City last year to invest in life, annuity and long-term care insurance — all forms of insurance that need higher investment income ratios to premiums because of the gap between when the premiums are paid and when the claims are made.

The Phoenix’s CEO, James Wehr, is retiring July 1, and will be replaced by Phillip Gass, Nassau Re’s CEO.

“I want to thank Jim Wehr for his leadership through a challenging period and market environment,” Gass said in a statement announcing the deal’s closing. “… Jim’s contributions over his three decades at Phoenix cannot be overstated, and we wish him all the best in his future endeavors.”

Kostas Cheliotis, Nassau Re’s chief operating officer and general counsel, will become Phoenix’s general counsel, effective immediately. John Mulrain, who had served as Phoenix’s general counsel and secretary since 2009, is retiring effective July 1.

Ernest McNeill Jr. will serve as chief financial officer, succeeding Bonnie J. Malley. He will also serve as Phoenix’s treasurer. Other members of Phoenix’s senior management team include Jody A. Beresin, chief administrative officer; Thomas M. Buckingham, chief operating officer; Robert J. Lombardi, chief actuary; Gina Collopy O’Connell, chief risk officer; and Christopher M. Wilkos, chief investment officer.

Phoenix’s common stock ceased trading at the close of market Monday. Stockholders will receive $37.50 per share.