WASHINGTON — Richard Fuld, former chief executive of Lehman Brothers Holdings Inc., yesterday said that regulators relied on flawed information in denying his now-defunct company aid that was extended to competitors.

“Other firms were hurt by their plummeting stock prices,’’ Fuld told the Financial Crisis Inquiry Commission. “Lehman was the only firm that was mandated by government regulators to file for bankruptcy. The government was then forced to intervene to protect those other firms and the entire financial system.’’

Lehman, the biggest underwriter of mortgage-backed securities when the US real estate market was at its peak, filed the largest bankruptcy case in the country’s history in September 2008, with $639 billion in assets, roiling markets and exacerbating the credit crisis.

The securities firm succumbed to the subprime mortgage crisis it had helped to create after surviving railroad failures of the 1800s and the Great Depression in the 1930s.

“Lehman was forced into bankruptcy not because it neglected to act responsibly or seek solutions to the crisis, but because of a decision, based on flawed information, not to provide Lehman with the support given to each of its competitors and other nonfinancial firms in the ensuing days,’’ Fuld said.

The collapse of New York-based Lehman and the bailout the same week of American International Group, a major insurer, contributed to the biggest rewrite of financial rules since the Depression as lawmakers sought to limit risk and create a process to unwind risky firms. The government also rescued carmakers.

Federal Reserve lending had “calmed markets’’ and allowed Lehman time to seek a solution to its “myriad problems,’’ Thomas Baxter, general counsel for the Federal Reserve Bank of New York, said in prepared remarks for yesterday’s hearing. “At no time, however, did anyone at the New York Fed believe that Lehman had sufficient liquidity to withstand’’ the crisis.

Baxter said AIG, with profitable insurance underwriting units, had resources to back a loan, unlike Lehman. The AIG rescue swelled to $182.3 billion.

The 10-member bipartisan commission was created by Congress to study the causes of the worst economic slump since the 1930s. It is scheduled to report its findings by December.

Fuld said Lehman sought permission in September 2008 to convert to a bank holding company, asked for its Utah bank to be able to raise deposits to boost liquidity, and proposed a ban on naked short selling. Regulators turned down the requests and then aided other firms with relief similar to what Lehman had asked for, he said.

Morgan Stanley and Goldman Sachs Group were allowed that month to become banks.

Federal Reserve general counsel Scott Alvarez said Lehman lacked sufficient collateral.

“They failed not because the government wasn’t willing to help them but because they were a victim of the circumstance and the economy and some bad decisions that they had made through the years,’’ he said.

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