The clock may be working against Joseph Sitt as his Thor Equities looks to sell a portfolio of retail properties.

Vacancies at properties such as 597, 590 and 530 Fifth Avenue could be pushing the landlord close to defaulting on his loans, Crain’s reported.

“Sitt could have problems because he bought at prices no one else would pay,” said Colliers International retail specialist Brad Mendelson.

Thor is certainly not the only property owner battling a cool retail market. Vacancy rates on Fifth Avenue between 42nd and 49th streets reached a high of 31 percent last year. And 8 of the 11 Manhattan retail neighborhoods tracked by Cushman & Wakefield saw availability rates climb between .6 percent and 8.2 percent. READ MORE