NRAM holds most of the bank's old mortgages and unsecured loans but Northern Rock PLC, the "good bank" holding savers' deposits and new loans, made a pre-tax loss of £142.6m.
This is the first set of results since Northern Rock was split into two.
Since 1 January, savers' money has been held by Northern Rock PLC, which was spun off from the old bank, now renamed NRAM.
NRAM said it was making good progress and chief executive Gary Hoffman said: "The company is continuing to show improving underlying profitability and 90% of the mortgage book remains fully performing" and that charges on bad loans had also fallen.
The percentage of mortgages in arrears rose slightly, but this was largely due to the overall number of mortgages shrinking.
NRAM also made a repayment of £300m to the government during the period, meaning it now owes £22.5bn to the Treasury.
Northern Rock PLC said that its financial performance in the first half was "in line with expectations", and that it was "continuing to prepare the business for a return to the private sector when conditions are right to do so".
The business lent almost £2bn to home buyers during the period, but lost almost the same amount in retail deposits, which fell to £17.6bn from £19.5bn at the start of the year.
