Investing legend Warren Buffett has made numerous blockbuster bets on stocks during his time leading Berkshire Hathaway Inc (NYSE:BRK)(NYSE:BRK). One of the more recent ones included raising the conglomerate's position in a leading insurance stock in the third quarter this year. The move appears to have paid off.



<h2>Buffett's Insurance Bet Gains</h2>



With less than a month left in 2025, there is a good chance that Berkshire Hathaway stock underperforms the S&amp;P 500, which is tracked by the SPDR S&amp;P 500 ETF Trust (NYSE:SPY).



But it won't be for lack of effort — Berkshire’s new positions, such as its third-quarter purchase of Alphabet Inc (NASDAQ:GOOGL) shares, have helped boost returns.



In addition to the new Alphabet position, the investment powerhouse’s 13F filing for the July-September quarter also revealed that it had cut back five of its positions and boosted the size of four others.



Berkshire ramped up its holding in the insurer Chubb Ltd. (NYSE:CB) by 16%, adding 4,299,111 shares to take the total position size to 31,332,895 shares as of end-September.



The shares have posted a 9.1% gain since then, raking in gains for Buffett's investment empire.



The stock closed at $282.25 on Sept. 30, valuing the Berkshire Hathaway position at $1,213,424,079.75.



Today, Chubb shares are worth $308.77. This suggests the Berkshire stake is now worth $1,327,436,503.47, translating to a gain of $830,948,375.40 for the stock since September. The shares added in the third quarter alone have added over $114 million in gains.



Berkshire started buying Chubb shares in 2023 and later revealed the stake in 2024 after a period of confidentiality to build a sizable position. 



<ul>
<li>Read Also: Warren Buffett Investment Success: 3 Simple Rules To Copy Oracle Of Omaha</li>
</ul>



<h2>Berkshire Trails The S&amp;P 500</h2>



In dollar amounts, Chubb is one of the top gainers in Berkshire’s portfolio since the end of the third quarter. It was the eighth largest holding for the investment firm at the end of the quarter.



The newly purchased Alphabet shares also made the Magnificent Seven stock a top 10 holding and that position is up significantly since September.



While those gains help the overall Berkshire Hathaway portfolio, they're still not enough for the conglomerate to get ahead of the S&amp;P 500.



Berkshire Hathaway shares have climbed 9.9% so far in 2025, while the S&amp;P 500 ETF Trust is up 13.3%.



With just weeks left before 2025 ends, this means there's a good chance that the last year of Buffett as CEO of Berkshire Hathaway goes down as a period of underperformance against the S&amp;P 500.



Berkshire Hathaway has beaten the S&amp;P 500 in three of the last four years and in 11 of the last 20 years.



Read Next: 



<ul>
<li>If You Invested $1,000 In Berkshire Hathaway Stock When Warren Buffett Did, Here’s How Much You’d Have Today</li>
</ul>



Image: Shutterstock

BRK.B

BRK.A

Berkshire Hathaway, led by Warren Buffett, increased its position in Chubb Ltd. by 16% in Q3 2025, resulting in an $830 million gain. Despite this, Berkshire Hathaway's overall performance in 2025 is trailing the S&P 500, with a 9.9% increase compared to the S&P 500's 13.3% rise. This underperformance comes in Buffett's final year as CEO.

- Warren Buffett's Berkshire Hathaway increased its stake in Chubb Ltd. by 16% in the third quarter of 2025, resulting in significant gains as the stock rose from $282.25 to $308.77.  
- Despite these gains, Berkshire Hathaway's performance trails the S&P 500, with a 9.9% increase in its shares compared to the S&P 500 ETF's 13.3% rise this year.  
- As 2025 concludes, it appears that Buffett's final year as CEO may be marked by underperformance relative to the broader market, despite past successes.  

Buffett's Big Insurance Bet Rakes In $830 Million Since September