Congressional stock trading is always a hot topic among retail investors, and a new disclosure from a U.S. senator is raising eyebrows — not just because of the trade itself, but because of how late it was reported. And oh, the missed profits.

Sen. John Hickenlooper (D-Colo.) recently disclosed the sale of Palantir Technologies (PLTR) stock, according to the MarketDash Government Trades page. The transactions were small — between $1,000 and $15,000 each — and were listed as being made by a child of the senator. The first sale happened on April 16, 2025, and the second on June 3, 2025. The problem? The filing was made on May 5, 2026 — roughly a year after both trades. Under the STOCK Act, members of Congress have 45 days to disclose stock trades by themselves or immediate family members. So this is a clear violation.

MarketDash reached out to Sen. Hickenlooper for comment and did not hear back.

"We just caught new STOCK Act violations. Senator John Hickenlooper JUST filed trades made last year. One of his children sold up to $30,000 of Palantir stock," Quiver Quantitative tweeted.

The disclosure also included a sale of $500,000 to $1,000,000 in shares of Liberty Broadband (LBRDK) by Hickenlooper's spouse on May 19, 2025 — again, nearly a year late.

There are no buy disclosures for Palantir from Hickenlooper, so it's unclear when his child acquired the shares. Based on a May 2025 filing, the child owned Palantir before Hickenlooper joined the Senate in 2021, or bought it before the end of 2024 without disclosure. Palantir stock traded between $8.90 and $33.50 in 2020, the year it went public.

But regardless of when the shares were bought, the timing of the sales is painful in hindsight. On April 16, 2025, Palantir traded between $89.62 and $97.30. Today, shares are at $138.32 — that's about 54% higher than the low on that sale day. The June 3 sale was closer to today's price (the stock traded between $130.10 and $135.28 that day), but still left additional gains on the table.

This isn't Hickenlooper's first STOCK Act issue. He was flagged for violations in 2022 by Business Insider. Colorado Newsline has also pointed out potential conflicts of interest: he bought shares of Eaton Corporation (ETN) while serving on the Senate Energy and Natural Resources Committee, and shares of Uber Technologies (UBER) while on the Senate Commerce, Science and Transportation Committee. Hickenlooper uses a third party to manage his investments, a practice he's had since his days as mayor of Denver in 2003.

According to Quiver Quantitative, Hickenlooper is worth $31.2 million and has made $16.6 million in stock transactions since joining the Senate in 2021. He's been a net seller each year through 2025: in 2025, he bought $1.45 million and sold $2.33 million. Prior to this latest late filing, his 2026 disclosures had all been within the 45-day window.