Clockwise from top left: 923 Fifth Avenue (credit: PropertyShark), Joseph Klaynberg, Bahar Tavakolian and the interior of Klaynberg's unit Ilan Bracha

Real estate developer Joseph Klaynberg and his wife, Emily, have sold their five-bedroom condominium at 923 Fifth Avenue for $10.9 million, according to city property records filed Feb. 8. The sale, handled by Ilan Bracha, founder of Keller Williams NYC, was the most expensive of last week.

Klaynberg is the founder of Wonder Works Construction, a development and construction firm that has worked on numerous New York City residential projects. A native of Minsk, he is now a senior managing director at Berkshire Capital Group, a private equity real estate investment firm headquartered in Manhattan. [more]

A few months after switching marketing firms from now-defunct JC DeNiro & Associates to Brown Harris Stevens, District’s developers have made another change, this time to Urban Marketing, a new division of brokerage Urban Sanctuary. Switching sales and marketing firms has become a common response from developers to slowing sales amid the recession. District, a 163-unit condominium at 111 Fulton Street, is currently over 70 percent sold out, said Stephen McArdle, a partner at Urban Marketing. [more]