Notorious Congress trader dumps entire stake in this Warren Buffett stock

Oklahoma Senator Markwayne Mullin disclosed on Nov. 21 that he fully liquidated his Berkshire Hathaway stake (trade dated Nov. 3), selling out ahead of a 9.52% rally in the shares; filings show he also sold full positions in Chipotle, T‑Mobile and Fiserv while making a $250k–$500k purchase of Microsoft. Berkshire has been under pressure this year from underwriting losses, FX hits, a large cash pile, constrained buybacks and investor repricing ahead of Greg Abel’s eventual leadership, and Mullin’s sale highlights poor timing and potential reputational risk. Given Mullin’s history of late filings and contentious trades tied to local public finance, the packet of disclosures is likely to renew scrutiny over conflict-of-interest and disclosure practices, though the market impact of his moves appears limited to optics rather than shifting fundamentals.

Analysis

Senator Markwayne Mullin disclosed on Nov. 21 that he fully liquidated his Berkshire Hathaway stake (transactions dated Nov. 3) and also sold full positions in Chipotle, T‑Mobile and Fiserv while making a $250,000–$500,000 purchase of Microsoft. His Berkshire exit preceded a 9.52% rally in the shares, highlighting poor timing and raising questions about the informational value of his trades.

Berkshire has faced multiple headwinds this year cited in the filing: underwriting losses, foreign‑exchange hits, an unusually large cash pile, constrained buybacks and investor repricing of the "Buffett premium" ahead of Greg Abel's expected leadership transition in 2026; these factors have contributed to elevated volatility and a negative sentiment score on BRK.B.

The disclosure renews governance and disclosure concerns given Mullin's history of late filings and municipal‑bond trades; market impact appears largely optical rather than fundamental (market impact score 0.28). Post‑trade performance has been mixed: Chipotle +3.94%, T‑Mobile +6.59%, Fiserv -1.77%, and the Microsoft purchase is down 5.13% since the trade.

Key Decisions for Investors

• Do not base portfolio moves solely on Mullin's transactions given demonstrated timing risk and limited evidence of informational advantage,
• For BRK.B monitor underwriting results, FX exposure, cash deployment and any change to buyback or acquisition plans and consider phased entries on clear improvement rather than immediate buying,
• Treat the Microsoft purchase ($250k–$500k, now down 5.13%) as a single, inconclusive data point and, if interested, size positions conservatively and use time‑weighted builds tied to fundamentals,
• Monitor regulatory/disclosure developments around senator trading and municipal‑bond conflicts as increased scrutiny could add episodic volatility and reputational risk to affected holdings