European financial institutions have been facing allegations of manipulating the London interbank offered rate, or Libor, since 2008. Many financial institutions have been forced to settle these allegations, including brokerage firm ICAP in September 2013 and bank UBS in December 2012.

Many of these financial institutions now face a new allegation: manipulating worldwide exchange rates. And this time, the investigation will take place over a wider area, as Switzerland has joined the U.S. in investigating the allegations.

According to The Wall Street Journal (WSJ), Swiss regulators announced on Oct. 4 that they are investigating several Swiss institutions for manipulating foreign-exchange markets. Finna, Switzerland’s main markets regulator, said that “multiple banks around the world are potentially implicated.”

The issue at hand is what is known as a “fix,” or a daily snapshot of exchange rates for various currencies across the globe. According to the WSJ, the most popular fix occurs at 4 p.m. London time, which often sees a given exchange rate reach its highest or lowest point in a given day. Regulators say one of the main violations is that banks bought or sold certain currencies ahead of the fix without clients’ permission in order to turn a profit.

This investigation could have wide-reaching effects in the U.S. market as well. The Bank for International Settlements says that the top five currency pairs exchanged each day deal with the U.S. dollar. The U.S. dollar/Euro combination comprises 24.1 percent of all exchanged currency, while the U.S. dollar and Japanese yen comprises 18.1 percent.

This crackdown on manipulating exchange rates could send litigation costs for financial institutions even higher. So far, four financial institutions have paid $2.7 billion to settle U.S. and British rate-rigging allegations dealing with Libor.