It's looking like Warren Buffett's swan song as CEO of Berkshire Hathaway Inc. (BRK) won't include beating the market. As 2025 winds down, the legendary investor is trailing the S&P 500—not exactly the exit he probably had in mind.

Several holdings in Berkshire's portfolio have dragged down performance this year, including Pool Corp (POOL), one of the conglomerate's more recent additions that looked promising just a few months ago.

When Good Bets Go Bad

Here's where things get interesting. Berkshire didn't just dip a toe into Pool Corp—they doubled down. Hard. The company's second-quarter 13F filing showed that Buffett and his investment team increased their position by a massive 136%. That came right after a 145% increase in the first quarter.

The buying spree started in the third quarter of 2024 when Berkshire first purchased 404,057 shares. By the end of June 2025, that position had ballooned to 3,458,885 shares. Clearly, someone at Berkshire really liked this stock.

Pool Corp, for those unfamiliar, is the world's leading wholesale distributor of pool equipment, parts, and supplies. Unfortunately for Berkshire, the company has missed analyst revenue estimates for three consecutive quarters, and the stock has paid the price.

The damage is real. Pool Corp trades at $251.87 today, down from $291.48 at the close of the second quarter on June 30. That means Berkshire's stake is currently worth about $871.2 million—down roughly $137 million since June. That's a 13.6% loss in just a few months on a position they were aggressively building.

Even Legends Have Off Years

Look, Warren Buffett will undoubtedly go down as one of the greatest investors of all time, regardless of how 2025 plays out. But the numbers don't lie.

Berkshire has beaten the SPDR S&P 500 ETF Trust (SPY) in 11 of the last 20 years, including three of the last four. But 2025? Not so much. Year-to-date, Berkshire is up 11.3% compared to the SPY's 16.9% gain. With less than two months remaining, it would take a strong finish to close that gap.

The next big reveal is coming this week. Berkshire's third-quarter 13F filing will show whether the company opened any new positions, closed out any holdings entirely, and—perhaps most interestingly—what they did with Pool Corp. Did they keep buying on the dip? Did they hold steady? Or did they start trimming?

Given that Pool Corp was one of Berkshire's recent favorites with significant position increases earlier in the year, investors will be watching closely to see if the trend continued or if the team decided to pump the brakes.