Monday, the US Federal Reserve Bank fined BNP Paribas $246 million in connection with a widespread scandal involving the fixing of currency markets, the BBC reports. In a press release, the Federal Reserve claimed to have “found deficiencies in BNP Paribas’s oversight of, and internal controls over, FX [foreign exchange] traders who buy and sell U.S. dollars and foreign currencies for the firm’s own accounts and for customer.”

“The firm [BNP Paribas] failed to detect and address that its traders used electronic chatrooms to communicate with competitors about their trading positions,” the statement continues.

In a statement of its own  following the Federal Reserve’s announcement, the bank said it “deeply regrets the past misconduct[,] which was a clear breach of the high standards on which the Group operates.”

That alleged “misconduct” occurred between 2013 and 2016. BNP says it has since “proactively implemented extensive measures to strengthen its systems of control and compliance.” Those measures include an “increase [in] resources and staff dedicated to [control and compliance], [the conduction of] extensive staff training and [the implementation of] a new Code of Conduct which applies to all staff.”

BNP, which operates in 75 countries and serves more than 30 million customers, has been penalized before for its involvement in the scandal. In May, the firm paid $350 million to the New York State Department of Financial Services in a settlement concerning “issues relat[ed] to oversight of its global foreign exchange business,” according to the BBC.

The Federal Reserve alone has levied $2 billion in fines connected to the scandal. Regulatory entities in Europe have also enforced penalties, though the UK’s Serious Fraud Office (SFO) closed its investigation into the matter in March 2016.

Barclays, the Royal Bank of Scotland, Deutsche Bank, and UBS have all been punished.

According to a separate BBC report by Sebastian Chrispin, traders can make substantial profits by manipulating currency exchange rates only slightly.  Traders at HSBC made $162,000 by artificially lowering the sterling-dollar exchange rate just .0035 pounds. In another case,  Citi traders made just under $100,000 by inflating the euro-dollar exchange rate.

Most institutions collect data on the foreign exchange market at the same time everyday—this collection is known as the “fix.” In London, for instance, the fix occurred daily during a strictly defined one-minute window around 4:00 pm. If traders “submit a rush of orders” (BBC’s words) just before the fix, they can give the impression of a spike or a trough in the market.

Alternatively, if traders gain confidential information regarding some event that will happen in the market, they can buy or sell so as to capitalize on the effect that event will have.

Both strategies are more effective if traders work together, either “actively”—by directly speaking with one another—or “implicitly”—by using subtle cues to inform each other as to what certain market participants plan to do.

The Federal Reserve alleges that BNP traders engaged in active collusion, sharing clients’ intentions via internet chatrooms. Such a breach of a client’s confidentiality could “skew his/her pension funds and investments,” according to Chrispin.

Still, some argue that this sort of manipulation of the foreign exchange market is a victimless crime, because the changes in exchange rates are too small to catch the attention of or have any real effect on everyday international travelers.

However, the perpetrators themselves, along with the institutions who failed to detect the traders’ activities, are certainly victims. Countless institutions have been hit with substantial fines, and traders have been fired, if not banned entirely from the industry.

In January, former BNP trader Jason Katz admitted to having “conspired” to manipulate the exchange rate between the US dollar and the South African Rand, and pleaded guilty to “violating US competition law.” The Federal Reserve “permanently prohibited [Katz] from participating in the banking industry,” according to its previously cited press release. The statement continues on to say the Federal Reserve will bar BNP  “from re-employing [all] individuals who were involved in the conduct underlying this enforcement action.”