"They're able to service the debt quite handily."
 Last year, the Equity O ffice portfolio turned a $713 million profit, according to financial data Blackstone reported to Bank of America. After interest payments, Blackstone pocketed north of $500 million last year, and it is on pace to repeat that feat again. That's a healthy return in a down market, since Blackstone only put $5 billion of its own cash into the $39 billion takeover. 
 Data from Trepp shows that Blackstone's Equity Office returns are being driven by favorable interest rates. 
 Goldman Sachs, the investment bank that securitized Blackstone's Equity Office debt, handed the private equity group low floating interest rates on its CMBS and mezzanine loans; current rates have Blackstone paying just 1.35 percent on its $4.9 billion CMBS loan, and 2.02 percent on $3.9 billion in mezzanine debt.