WASHINGTON — The Securities and Exchange Commission on Friday brought civil fraud charges against six former top executives at Federal National Mortgage Association and Federal Home Loan Mortgage Corp., saying they misled investors about risky subprime loans the mortgage giants held when the housing bubble burst.

Those charged include the agencies’ two former CEOs, Fannie’s Daniel Mudd and Freddie’s Richard Syron. They are the highest-profile individuals to be charged in connection with the 2008 financial crisis.

Mudd, 53, and Syron, 68, led the mortgage giants in 2007, when home prices began to collapse. The four other top executives also worked for the companies during that time.

The lawsuit was filed in federal court in New York City.

“Federal National Mortgage Association and Federal Home Loan Mortgage Corp. executives told the world that their subprime exposure was substantially smaller than it really was,” said Robert Khuzami, SEC’s enforcement director. “These material misstatements occurred during a time of acute investor interest in financial institutions’ exposure to subprime loans, and misled the market about the amount of risk.”

The Justice Department has opened up probes into Fannie and Freddie but has not charged anyone with a crime.

In a statement released through his attorney, Mudd said the lawsuit “should never have been brought” and said the government reviewed and approved all of the company’s financial disclosures.

Syron’s lawyers said the case was “without merit,” and said the term “subprime had no uniform definition in the market” at that time.

Fannie and Freddie buy home loans from banks and other lenders, package them into bonds with a guarantee against default and then sell them to investors around the world. The two own or guarantee about half of U.S. mortgages, or nearly 31 million loans.

During the financial crisis, the two firms verged on collapse. The Bush administration seized control of them in 02008.

So far, the companies have cost taxpayers almost $150 billion — the largest bailout of the financial crisis. They could cost up to $259 billion, according to its government regulator.

The other executives charged were Fannie’s Enrico Dallavecchia, 50, a former chief risk officer, and Thomas Lund, 53, a former executive vice president; and Freddie’s Patricia Cook, 58, a former executive vice president and chief business officer, and Donald Bisenius, 53, a former senior vice president.