American banking major Goldman Sachs has been fined £17.5 million by UK's City regulator the Financial Services Authority (FSA).
The FSA investigation got under way in April after the US Securities and Exchange Commission (SEC) charged the firm with misleading buyers of complex mortgage-backed investments in 2007, at the time of the collapse of the US housing market.
In a settlement in mid-July, the bank agreed to pay £356 million ($550m million) - the largest fine in the SEC's history.
According to the FSA Goldman failed to disclose that Fabrice Tourre, the trader accused by the SEC of being the key figure in the mortagage-backed securities deal was under investigation.
Tourre took over as the company's executive director at its London office in late 2008, which saw his business dealings come under the UK regulator's jurisdiction.
Denying any wrongdoing Tourre asked a federal court to throw out the SEC case.