The deals would make the 1.5-million-sf Central Loop asset anchored by Bank One worth $422 million.

Prime Group Realty Trust owes $163.1 million on a construction loan from HypoVereinsbank that comes due in January. Although the loan at 3.92% can be extended another year, the partners plan to pay it off if they gets a new mortgage. The REIT also has a $75-million mezzanine loan from LNR Property Corp. at 16% interest due in January.

After paying off those Bank One Center debts, Prime Group Realty Trust says it plans to set aside $22.5 million for tenant improvements that could be spent to help lease the remaining 500,000 sf.

Estein & Associates USA Ltd. would get a 10% return on its investment. Prime Group Realty Trust would also get a 10% return, but only after Estein & Associates USA is paid. Excess cash flow, as well as proceeds from a sale or refinancing, would be split 50-50 between the two parties, according to a deal expected to close Oct. 15. Prime Group Realty Trust will continue to be in charge of leasing and management of the building, which has seen occupancy stall at around 70%.

Although its financial picture has improved in recent months, Prime Group Realty Trust is exploring potential sales of its city and suburban office and industrial assets, as well as an outright sale of the entire REIT.