Alfa Financial Software's billion dollar initial public offering in London Friday marked the British capital's largest listing of the year and came after the Brexit vote left a string of debutants facing a crisis of confidence in the second half of 2016.

Alfa stock began conditional trading Friday after floating at a price of 325 pence per share, raising which earned the tech firm a valuation of £925 million ($1.2 billion).

The company makes customer management software that enables asset-backed financing houses to remain compliant in an ever-evolving regulatory environment. It counts Bank of America (BAC - Get Report) , Barclays (BCS) and Nordea (NRDEF) among its clients.

Asset backed financing is where companies take out loans from lenders and pledge assets of various kinds as collateral to be held against the debt.

Just more than 25% of Alfa was sold in the deal, by the company's founders and other early investors, raising proceeds of around £254 million.

The deal is the largest for London so far in 2017, given a quiet IPO market that has been affected by both uncertainty over the forthcoming Brexit negotiations as well as the fallout from the country's vote to leave the European Union last year.

Bain Capital-backed TI Fluid Systems pulled the plug on its $630 million London IPO late in October while, earlier in the month, Vista Equity Partner's backed financial software firm, Friday's initial public offering of , pulled also cancelled a sale of itself.

Colostomy bag maker, Convatec Group, and waste management firm, Biffa, both went ahead with their deals around the same time although each took chip off the prices that they were originally hoping to achieve.