WASHINGTON — Rep. Chellie Pingree, a Democrat representing Maine’s 1st Congressional District, wants to ban federal lawmakers from making personal financial trades that could conflict with their public service.

But Pingree disclosed this week that she violated an existing law — the Stop Trading on Congressional Knowledge Act — by failing to properly disclose a sizable purchase of U.S. Treasury securities, according to a federal financial disclosure document reviewed by the Portland Press Herald.

On Feb. 5, Pingree purchased six Treasury securities that together are worth between $90,000 and $300,000, the document indicates.

But she didn’t disclose the purchases until Wednesday — nearly three months after the STOCK Act’s deadline for publicly disclosing such transactions. Each Treasury security carries an interest rate of between 3.875% and 4.625%.

Pingree on Friday acknowledged her STOCK Act violation, telling the Portland Press Herald that “a paperwork error” caused the snafu.

“Once I discovered this issue, I rectified it immediately and filed the necessary paperwork,” Pingree said in an emailed statement.

Asked if Pingree’s office had discussed the matter with the Committee on House Ethics, which enforces STOCK Act violations, Pingree spokesperson Gabrielle Mannino said it had not — although she confirmed that the congresswoman had already paid a standard $200 penalty for the late disclosure.

Pingree joins dozens of other members of Congress who have this decade violated the STOCK Act’s disclosure and transparency provisions, which are designed to reveal potential conflicts of interest and defend against insider trading.

Other lawmakers — including Reps. Marjorie Taylor Greene, R-Ga., and Julie Johnson, D-Texas, have faced criticism in recent weeks for making six- and seven-figure stock trades timed closely to President Donald Trump’s “Liberation Day” tariff declaration on April 2, which temporarily caused financial markets to tank.

Pingree’s late disclosures also come as a bipartisan coalition of federal lawmakers has introduced several similar bills that generally aim to prohibit members of Congress from personally buying and selling certain financial investments altogether, while enhancing penalties for those who violate conflict-of-interest laws.

While no single measure has yet received a vote, key political leaders including Trump, House Speaker Mike Johnson, R-La., and House Minority Leader Hakeem Jeffries, D-N.Y., have each expressed varying degrees of support for more muscular laws governing members of Congress’ personal financial trading — particularly stock trading.

Pingree does not own individual stocks, according to her most recent annual financial disclosure, which covers her personal finances through 2023. Her wealth is primarily concentrated in exchange-traded funds, Treasury securities, real estate and a Paloma Partners investment fund.

“The STOCK Act was a step in the right direction, but it has proven insufficient in holding members accountable,” said Jamie Neikrie, legislative director for nonpartisan government watchdog group Issue One, and described Pingree’s STOCK Act violation as “just another example.”

Neikrie added that “this is not a partisan issue, it’s a matter of basic ethics and accountability.”

Pingree said that she continues to count herself among federal lawmakers who want stronger financial trading rules for Congress.

Before Friday, she had not sponsored or co-sponsored a bill that would do so in the current session, according to congressional legislation records, although she said she was considering the matter.

“I have supported bills to ban and limit members of Congress from trading stocks in the past and will again during this Congress,” Pingree said.

Rep. Jared Golden, a Democrat representing Maine’s 2nd Congressional District, is an original co-sponsor of the current TRUST in Congress Act, one of the financial trading bills that has gained the most bipartisan interest since its introduction in January.

Mannino, a spokesperson for Pingree, later confirmed that the congresswoman, who had co-sponsored a failed version of the bill in the last congressional session, on Friday signed on as a co-sponsor to the current proposal pending before Congress.

Introduced by Rep. Seth Magaziner, D-R.I., the TRUST in Congress Act had so far been co-sponsored by 76 lawmakers ranging from far-right Republican Reps. Chip Roy of Texas and Nancy Mace of South Carolina to far-left Democratic Reps. Rashida Tlaib of Michigan and Ro Khanna of California.

Dave Levinthal is a Washington, D.C.-based investigative journalist who regularly reports on political money and ethics issues.