London Capital posts a pre-tax loss of £56,000 for the year to the end of December compared with a profit of £5.8m last time.
It said this was due to a £3.2m software impairment and the provision of £3.2m for a Financial Ombudsman Service revised assessment - both of which had been announced previously.
Adjusted pre-tax profits rose 8% to £6.5m while total turnover was up 25% at £34.5m.
Adjusted earnings before interest, tax, depreciation and amortisation increased 5% to £8.5m.
CEO Simon Denham said: "It has been a challenging year on a number of fronts but we remain positive about the future of the business.
"We have invested significantly in our products, platforms and people and believe the company is now well positioned to take advantage of these changes.
"Whilst there is little visibility in forecasting earnings I am pleased to report that trading in 2011 has started well."