BOSTON -- Real estate analysts say a wealthy Boston investor is well on his way to creating the city's biggest mansion ever in the Back Bay, one with 24,000 square feet and 15 bathrooms.

The $23 million mansion at the corner of Commonwealth Avenue and Exeter Street is being built for investment executive Ofer Nemirovsky, according to the Boston Globe.

Nemirovsky purchased several condos and a townhouse over the past several years in order to combine them into one pricey, luxurious mansion that will include a glass atrium and walkway, elevator, media room and library and basement ball playing court.

Nemirovsky is the managing director of HarbourVest, an international private equity firm in Boston, according to the Globe.

Local real estate agents say the mansion may be part of a trend that has the region's wealthiest residents moving back into the city center and consolidating some of Boston's Gilded Age properties back into private residences.

They said last year former real estate exec and the son of the EMC Corp. founder, Christopher Egan, agreed to pay more than $15 million for the Gamble Mansion at 5 Commonwealth Ave. It had been used for classrooms by the Boston Center for Adult Education since 1941.

The Nemirovskys, high-profile philanthropists who currently live in Cambridge, have been acquiring the Back Bay properties since 1997, the Globe said.