BRK-B vs WTM: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. BRK-B and WTM share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined BRK-B and WTM exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

Berkshire Hathaway is a diversified holding company that owns a wide range of businesses outright and holds a large portfolio of public stocks. Its foundation is insurance: GEICO, Berkshire Hathaway Reinsurance, and other insurers generate underwriting profit and, more importantly, float (premiums held before claims are paid) that Berkshire invests. In Q1 2026 insurance underwriting income rose to about $1.72 billion from $1.34 billion a year earlier. Beyond insurance, Berkshire owns the BNSF railroad, Berkshire Hathaway Energy, and consumer and industrial businesses such as Duracell, Dairy Queen, See's Candies, and Precision Castparts, alongside a stock portfolio historically anchored by names like Apple and American Express.

Full BRK-B guide

White Mountains Insurance Group is a holding company, not an insurer that happens to own a few other things. Its capital sits in four reported segments: Ark and the WM Outrigger sidecar, which underwrite specialty insurance and reinsurance largely at Lloyd's; Kudu Investment Management, which buys minority stakes in boutique asset and wealth managers and collects a share of their revenue; HG Global, the reinsurance arm behind municipal bond insurer BAM; and Distinguished, a specialty program manager placing more than ~$550 million of premium a year, majority-acquired in 2025 for ~$230 million. The business everybody still asks about, Bamboo, is mostly gone: White Mountains agreed in October 2025 to sell control of the California homeowners MGA to CVC funds at a ~$1.75 billion valuation, taking ~$840 million of net cash and keeping roughly 15%. Liam Caffrey became chief executive on January 1, 2026, after four years as chief financial officer.

Full WTM guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• BRK-B drivers: Leadership transition to Greg Abel; Insurance float and underwriting.
• WTM drivers: Redeploying the Bamboo proceeds; Ark and WM Outrigger in a softer market.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: The central 2026 risk is the leadership transition itself: Buffett's judgment and reputation were core to Berkshire's edge, and the market will test whether Greg Abel can allocate capital as effectively, especially with a record cash pile to deploy. For WTM, catastrophe is the clearest one.

Growth-minded investors who believe the theme has years to run tend to accept the richer multiple for more upside; value-minded investors lean toward the cheaper forward earnings and steadier profile. Pick BRK-B if you believe its drivers more; WTM if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the BRK-B and WTM guides.

BRK-B. Figures are approximate and tied to the asOf date; verify live numbers before acting. Because accounting rules force Berkshire to mark its large stock portfolio to market each quarter, GAAP net income is noisy, so investors typically focus on operating earnings and book value per share rather than a simple P/E. The record cash balance means a meaningful part of the market cap is cash awaiting deployment, which affects how the business should be valued.

WTM. White Mountains retired its adjusted book value per share measure in 2025, so plain GAAP book value per share is now the headline figure and the one management is scored on. Price to book, not a price to earnings or price to sales multiple, is the relevant comparison, because reported revenue moves with whichever subsidiaries were consolidated that year. The repurchase price is a useful cross-check: the company paid about 93% of book value for its own stock in the second quarter of 2026.

Headline figures (approximate, Jul 2026): BRK-B shows operating earnings (q1 2026) ~$11.35 billion, up ~18% year over year (approximate; verify live), net earnings (q1 2026) ~$10.1 billion, but volatile due to mark-to-market swings on equities (approximate; verify live), cash and treasurys ~$397 billion at end of Q1 2026, a record (approximate; verify live), market cap ~$1 trillion (BRK-B ~$497 per share in mid-July 2026; approximate; verify live); WTM shows book value per share (june 30, 2026) ~$2,258, price to book ~0.95x, book value per share growth ~4% in Q2 2026, ~3% for the first half including dividends, common shareholders' equity ~$5.39 billion.

BRK-B and WTM are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined BRK-B and WTM exposure against your real portfolio. It is not an investment adviser.