Very and Littlewoods owner Shop Direct swung to a loss in its third-quarter after it booked £100m to pay PPI claims.
Accounting for this additional cost, Shop Direct made a £10.7m pre-tax loss in the nine months to the end of March.
The online department store said it made the provision because the PPI claim deadline has been extended until August 2019.
In the financial year to date, it has paid out almost £80m in claims.
Group sales jumped 1.6% to £1.5bn and customer numbers advanced by one million, driven by its Very brand where revenue spiked 10.6%.
Shop Direct said Very continues to “outpace the online retail market”.
Sales at Littlewoods declined 15% to £445m.
The etailer, which appointed new boss Henry Birch in March, said: “We continued to benefit from our department store model, which provides resilience against adverse movements in individual product categories.”