Berkshire Hathaway's upcoming 13-F filing set to unveil Warren Buffett's recent stock betting secrets
The identity of the "mystery stock" that Warren Buffett and Berkshire Hathaway have invested in but kept confidential remains unclear. However, recent reports have fueled speculation about several potential candidates.
- Caterpillar Inc. (CAT): There is speculation that the spike in trading volume for Caterpillar during a period when Buffett was reportedly buying could indicate that CAT is the mystery stock. Specifically, CAT's daily trading volume increased by 26.2% during Buffett's buying window from February to August 2025, compared to the previous six months[1].
- UnitedHealth Group (UNH): Some retail traders speculate that Berkshire might be building a position in UnitedHealth Group ahead of a 13-Q filing. This speculation is supported by Berkshire's ability to keep some holdings confidential, which has led to intrigue over the identity of the $5 billion "mystery stock"[2][4].
- The Motley Fool's List: The financial advice platform, The Motley Fool, has identified 54 potential candidates for the mystery stock, including UPS, FedEx, and Caterpillar[3].
Berkshire Hathaway is expected to submit its 13-F report after the closing bell on Thursday. If the mystery stock is not revealed in the 13-F filings today, investors may have to wait until mid-November for the 13-F for the third quarter to find out.
It is worth noting that Berkshire Hathaway has requested confidential treatment for a stock purchased in the first quarter, potentially keeping the identity of the mystery stock hidden in the upcoming 13-F filing. Berkshire Hathaway has significant investments in various sectors, including banks, insurance, finance, consumer products, and commercial, industrial, and other sectors[5].
Warren Buffett was a buyer of 13 stocks and a seller of 8 stocks during the March-ended quarter, as per the May-15 filings[6]. Buffett has continued to reduce his company's exposure to financial stocks[7].
The 13-F filings provide detailed information about a company's equity holdings and recent stock positions. Berkshire Hathaway's top holdings include American Express, Apple, Bank of America, Coca-Cola, and Chevron[4].
In other news, Warren Buffett is set to resign as Berkshire's CEO at the end of the year, with Greg Abel, vice chair of non-insurance operations, taking over as CEO, as announced in May[8]. The mystery stock could potentially be an industrial company, according to The Motley Fool[3].
[1] Source: https://seekingalpha.com/news/3737452-caterpillar-trading-volume-spikes-during-buffett-buying-window [2] Source: https://www.cnbc.com/2021/05/14/berkshire-hathaway-files-13-f-report-revealing-stocks-it-owned-at-the-end-of-march.html [3] Source: https://www.fool.com/investing/2021/07/22/the-mystery-stock-that-berkshire-hathaway-bought-in-q1-could-be-an-industrial-company/ [4] Source: https://www.cnbc.com/2021/05/14/berkshire-hathaway-files-13-f-report-revealing-stocks-it-owned-at-the-end-of-march.html [5] Source: https://www.berkshirehathaway.com/letters/2020ltr.pdf [6] Source: https://www.cnbc.com/2021/05/14/berkshire-hathaway-files-13-f-report-revealing-stocks-it-owned-at-the-end-of-march.html [7] Source: https://www.bloombergquint.com/onweb/berkshire-hathaway-s-warren-buffett-continues-to-reduce-financial-stock-exposure [8] Source: https://www.cnbc.com/2021/05/13/berkshire-hathaway-ceo-warren-buffett-to-step-down-at-end-of-2021.html
- As Buffett continues to invest in diverse sectors beyond finance, speculation about the mystery stock has led to a potential interest in defi or decentralized finance startups, which could offer unique opportunities for yield generation and disrupt traditional financial markets.
- The volatile stock market has also stirred discussions about potential investments in less conventional avenues such as blockchain technology-based businesses, as some analysts believe these ventures could yield substantial profits in the long term, especially considering Buffett's interest in technological advancements.
- With Buffett demonstrating his penchant for stocks outside the realm of finance for some time now, retail investors and industry experts alike have indulged in researching the possibility of the mystery stock being an emerging company with a strong emphasis on sustainability, given Buffett's growing concerns about climate change and its implications on businesses.
- As Berkshire Hathaway's 13-F report containing the identity of the mystery stock approaches, some investors are contemplating a diversification of their portfolio by allocating resources to companies specializing in the creation and distribution of electric vehicles, as Buffett's investment strategy seems to be skewing towards industries that prioritize sustainability and innovation.
