Several media outlets are reporting that in Paris, the offices of five major banks were searched Tuesday as part of an investigation into suspected money laundering and tax evasion in relation to dividend payments.

Le Monde, which was the first outlet to break the story, reported, the raids were launched at the offices of Societe Generale, BNP Parabas, Exane and Natixis, as well as the offices of British banking titan HSBC.

Reuters was able to confirm that the offices of Societe Generale were searched, although the bank offered no further comments. The other four banks all refused to comment on the matter.

In a statement, France’s National Financial Prosecutor’s Office (PNF) confirmed the reports of the raids. It said the probe was related to what is called the “cum-cum” dividend strategy, whereby ahead of a dividend payout, a bank temporarily will transfer shares of a stock to a foreign investor, to avoid having to pay a dividend tax.

In that case, the dividends are then not taxed, or if taxes are paid, the taxes are refunded to the foreign investor. The shares can then be resold to the original owner, and the two parties will split the amount which would otherwise have been taken as tax, had the transfer not occurred.

According to PNF, the investigation began back in 2021, and it is being performed by 16 investigating judges, and more than 150 agents. Bloomberg is reporting that the five banks will be facing collective fines in the range of over €1 billion ($1.1 billion) as a result of the investigation.

The investigation has served as yet another blow to investor confidence in the stability of the global banking industry, as the sector continues to reel from numerous bank failures in the United States, as well as the near-failure of Swiss banking giant Credit Suisse, which was only averted by a government brokered takeover by its larger rival, UBS.