Plus500 sponsor Athletico Madrid, pictured here playing against Barcelona's Lionel Messi
The Israel-based but London listed company's shares went into free fall after Plus500 said it suspended around 55% of its UK trading accounts as it re-ran anti-money laundering checks.
Around £300 million ($465.56 million) was knocked off Plus500's value after shares closed down 37%. They're still falling today, down a further 8%.
But analysts at Liberum have tried to work out a more concrete estimate of what the freeze will cost the company, beyond lost value.
Analyst Cormac Leech thinks the incident could lose Plus500 between $25-39 million (£16.11-£25.13 million) in revenue this year.
That's between 9-14% of the total $280 million (£180.43 million) revenue Plus500 told investors to expect this year - a big chunk.
Leech's estimate is based on forecasting how many customers affected by the freeze could leave. He estimates up to half of those hit might abandon the site - mainly casual users with little in their trading accounts who can't be bothered to send off documents to re-verify their identities. His minimum assumption is 33% of those frozen will leave.
There's also the harder to calculate cost of what this could do to Plus500's business in the future.
Leech says: "The broader question is the reputational impact on the Plus500 brand which may, for at least a couple of months, adversely impact average user acquisition costs, churn and valuation multiples."
But Liberum still thinks Plus500's extreme price crash yesterday was an over reaction and the investment bank keeps a 'buy' recommendation on the company.