Seven banks are at the center of a probe by Mexico’s antitrust regulator looking into possible collusion to manipulate bond prices, according to a person with knowledge of the matter.

The investigation is focused on the so-called market makers that can buy notes from the government and state-owned companies in primary auctions -- local units of Banco Santander SA, Banco Bilbao Vizcaya Argentaria SA, JPMorgan Chase & Co., HSBC Holdings Plc, Barclays Plc, Citigroup Inc. and Bank of America Corp. -- according to the person, who asked not to be identified because the information is private.

Some of the banks have already received requests for information related to the investigation, which could also extend to other participants in both the primary and secondary bond markets, the person said. One institution has agreed to cooperate with the probe -- the outlines of which were announced by regulators last month -- in exchange for a lighter punishment, according to two people familiar with the matter.

The case threatens to upend a local sovereign and quasi-sovereign debt market with more than $400 billion of securities outstanding as officials probe whether the parties coordinated bids to suppress prices and increase yields for holders, costing the government and companies in higher interest rates. It shows Cofece, as the antitrust regulator is known, flexing its muscles weeks after fining the country’s biggest pension funds as well as 11 individuals for colluding to make it difficult for clients to transfer their accounts.

When it announced the investigation April 19 without identifying the targets, Cofece said the damage to public finances “could be serious” and noted that daily trading volume in the market is about 100 billion pesos ($5.4 billion). In an email to Bloomberg News, Cofece said that the agency made aspects of the probe public with the goal of attracting informants and that any entities under investigation haven’t necessarily committed wrongdoing.

JPMorgan spokeswoman Tasha Pelio, Bank of America spokesman Bill Halldin, Barclays spokesman Marc Hazelton and HSBC spokeswoman Lyssette Bravo declined to comment on the investigation or say whether their banks had been contacted by authorities. Press offices of Citibanamex, BBVA and Santander Mexico also declined to comment.

Mexico’s probe is the latest investigation of potential collusion by banks, which have been hit with multi-billion dollar fines around the globe for manipulating markets. In January, U.S. prosecutors charged workers from some of the world’s biggest banks with conspiring to coordinate trading of dollars and euros and manipulate prices through discussions in an electronic chat room known as “The Cartel.” Federal prosecutors have subpoenaed several banks as part of a criminal investigation into possible manipulation of the U.S. Treasuries market, according to people familiar with the matter.

Cofece’s highest fine for monopolistic practices is 10 percent of a company’s annual income, a limit that likely means the damage from the market manipulation may be much larger than any penalty the government would collect.