<\/p>\n
A stock can look very different six months after purchase, especially when its price has fallen way below the original entry point. <\/p>\n
Most investors hold on, waiting for the price to recover rather than locking in a loss. A pattern one of the most successful investors alive says causes lasting financial damage. <\/p>\n
In his 2024 letter to Berkshire Hathaway shareholders, Warren Buffett identified a behavioral pattern he called “the cardinal sin” of managing a business. <\/p>\n
His late partner, Charlie Munger, had a blunter label for the habit of sitting on known problems and hoping they disappear on their own: “thumb-sucking.”<\/p>\n
Buffett admitted to misjudging businesses, managers, and capital allocation at Berkshire<\/p>\n
Buffett’s candor in the 2024 Berkshire Hathaway annual letter went beyond a single line about thumb-sucking.<\/p>\n
“The cardinal sin is delaying the correction of mistakes or what Charlie Munger called ‘thumb-sucking.’ Problems, he would tell me, cannot be wished away. They require action, however uncomfortable that may be,” Buffett wrote in the annual Letter.<\/p>\n
His argument was direct: once you know something is broken, every quarter you wait to act compounds the cost.<\/p>\n
Berkshire’s own Alphabet position illustrates what that delay looks like at scale. <\/p>\n
At Berkshire’s 2017 annual meeting, Buffett and Munger acknowledged missing Google as their worst mistake in tech, with Buffett citing GEICO’s Google ad spending as direct insight into the business. <\/p>\n
Two days later, on CNBC’s “Squawk Box,” Buffett called Google “an extraordinary business” with “some aspects of a natural monopoly.” Berkshire did not open a position for another eight years. <\/p>\n
The firm opened its first Alphabet stake in the third quarter of 2025, buying 17.85 million shares valued at roughly $4.3 billion, and by the Q2 2026 13F filed August 14, 2026, that stake had grown to roughly 106 million shares, making Alphabet Berkshire’s third-largest holding, in a company Buffett had said Berkshire should have owned sooner.<\/p>\n
The SEC identified a behavioral bias that explains why investors hold losing stocks<\/p>\n
Behavioral researchers have given the pattern Buffett described a clinical name that appears in federal investor education materials.<\/p>\n
The SEC’s Office of Investor Education and Advocacy calls it the disposition effect, based on a Library of Congress report the agency commissioned in 2010. <\/p>\n
The report describes it as investors’ tendency to hold losing investments too long while selling winning investments too soon.<\/p>\n
More Warren Buffett:<\/p>\n
Warren Buffett reveals he broke his own investing pattern<\/p>\n
Warren Buffett has a blunt take on today’s market<\/p>\n
Warren Buffett pulls no punches on stock market for 2026<\/p>\n
Terrance Odean, now a professor of finance at the University of California, Berkeley, tested the effect using 10,000 brokerage accounts. <\/p>\n
His 1998 Journal of Finance study found that investors were roughly 1.5 times as likely to sell their winning positions as their losing ones.<\/p>\n
That lopsided emotional math pushes investors to hold falling positions, because selling would force them to register the loss as permanent rather than temporary.<\/p>\n
The SEC calls it the disposition effect: investors often sell winning stocks too soon while holding losing positions, hoping they recover eventually.<\/p>\n
Michael M. Santiago \/ Getty Images<\/p>\n
One question can reveal whether patience or avoidance is driving your portfolio decisions<\/p>\n
Shefrin and Statman’s 1985 Journal of Finance paper, titled “The Disposition to Sell Winners Too Early and Ride Losers Too Long: Theory and Evidence,” later described in the SEC bulletin, identified the desire to recover the original purchase price as its core driver. <\/p>\n
One reframing test, popularized by fund manager Peter Lynch in One Up on Wall Street and echoed in behavioral finance literature, captures the spirit of Buffett’s warning: ask whether you would buy the same stock today, at its current price, with cash sitting idle in a savings account.<\/p>\n
A “no” separates a sound reassessment from an avoidance decision, but it does not, in itself, dictate a sale, tax treatment and time horizon shape what comes next, Certified Financial Planner Board guidance noted. <\/p>\n
What Buffett’s thumb-sucking test means for your next portfolio review<\/p>\n
Buffett drew a clear line in his letter between patience built on a sound investment thesis and inaction driven by emotional avoidance. The second kind persists because admitting a mistake often feels worse to an investor than watching the position continue to lose value.<\/p>\n
The winning stocks investors sold went on to outperform the losing stocks they kept by 3.4 percentage points over the following year, Odean’s study found. <\/p>\n
Every dollar locked in a holding with deteriorating fundamentals is a dollar unavailable for a position with stronger current prospects, and every quarter of delay is one where the compounding runs the other way.<\/p>\n
Related: Warren Buffett named these 3 stocks as favorites for a reason<\/p>\n
#Warren #Buffett #explains #investing #sin #Munger #called #039thumbsucking039<\/p>\n","protected":false},"excerpt":{"rendered":"
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