Warburg Pincus declined to release financial details of the transaction. However, a spokesman for Houlihan Lokey Howard & Zukin, the international investment bank that served as Brandywine's financial advisor, puts the number at "approximately $150 million."

"We're pleased to have found an excellent partner as we look to develop into a leader in the senior housing industry," says Brenda Bacon, Brandywine's CEO. "Warburg Pincus brings experience in both the healthcare and real estate sectors."

"Given the growing population of aging baby boomers, we're targeting senior housing for investments," says Patrick Sullivan, a WP managing director. "Brandywine is our first investment in this space, and we expect to rapidly grow the company through acquisition and development."

The sale is the final step in a process that has morphed Brandywine Senior Care and effectively taken the company out of the nursing home business. Indeed, as part of the deal the company will be renamed Brandywine Senior Living. Prior to the sale to WP, Brandywine had shed, in two separate transactions netting $134 million, nine skilled nursing and rehab centers.

In the first of the sales back in February, Brandywine sold two facilities in Pennsylvania to Extendicare for $27 million. And in the deal that finally triggered the stock sale, the company sold seven New Jersey facilities to the Mississauga, ON-based Retirement Residences REIT for $107 million including working capital. The latter transaction, first reported by GlobeSt.com in March as being under contract, closed in June. "It allowed us to expand our existing platform in the northeastern US," says Retirement Residences president/CEO Derek Watchorn.

"It was a complicated, multifaceted process," Bacon says. "It allowed us to maximize shareholder value while at the same time transferring the ownership of our skilled nursing facilities to companies we believe will maintain our commitment to the properties."

The 10-year-old Brandywine currently operates a total of nine assisted living facilities with approximately 1,000 active beds in New Jersey, Pennsylvania and Delaware. "We expect to continue to build, acquire and manage additional sites in clusters both in and outside of the Mid-Atlantic region," Bacon says.