Ladder Capital Realty Finance, a newly-organized REIT that planned to invest in commercial real estate loans, postponed its IPO on Tuesday. It was the second consecutive mortgage REIT to postpone its IPO after Foursquare Capital postponed its deal last week. In a sign of weakened demand for mortgage REITs, both of the postponements came after the three prior mortgage REIT IPOs, Colony Financial (CLNY), Apollo Commercial (ARI) and CreXus (CXS), all had to significantly cut their proposed deal sizes to go public. J.P. Morgan, Wells Fargo and Citi were set to be the lead underwriters on the Ladder deal.