BRK-B vs PRM: 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.

Reading it: PRM is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

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 PRM 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 PRM 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

Perimeter Solutions, Inc. (NYSE: PRM) is a Clayton, Missouri industrial company that runs two reporting segments. Fire Safety formulates and manufactures aerial long-term fire retardants and fire suppressant foams, and it supplies the equipment and the resupply service network behind them, covering roughly ~150 air tanker bases across North America. That segment produced ~$489.0 million of net sales and ~$290.5 million of segment adjusted EBITDA in fiscal 2025, a margin near ~59%, and it sits on top of contracts rather than open-market demand: a sole-source USDA Forest Service aerial retardant award announced in September 2025 with a potential value of ~$1.12 billion over five years, a CAL FIRE renewal covering 2026 to 2031 with pricing brought in line with other large retardant customers, and a Defense Logistics Agency indefinite-delivery contract for aqueous film forming foam with a ~$500 million ceiling and an ordering period running to April 29, 2031. Specialty Products is the other half of the story and is being built by purchase: lubricant additives through Phosphorus Derivatives (phosphorus pentasulfide), electronic and electro-mechanical components through Intelligent Manufacturing Solutions, electro-optical product lines bought for ~$40.0 million in November 2025, Medical Manufacturing Technologies acquired from Arcline for ~$685 million in January 2026, and Monaco Enterprises, a life safety and emergency management systems supplier to US government facilities, for ~$120.0 million on July 30, 2026.

Full PRM 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.
• PRM drivers: A contracted federal retardant franchise; Specialty Products as the deliberate second leg.

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 PRM, the founder advisory structure is the single largest non-operating claim on this company: at June 30, 2026 the fixed amount was carried at ~$167.5 million and the variable amount at ~$1,093.6 million, roughly ~$1.26 billion combined against a ~$5.15 billion market value, with ~$630.6 million already sitting on the balance sheet as a related-party liability and ~$95.7 million settled in cash during the first half of 2026, and because at least half is settled in shares it dilutes as well as costs.

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; PRM 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 PRM 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.

PRM. Figures are approximate, stamped to August 2026 and drawn from the Q2 2026 10-Q, the July 31, 2026 earnings release and the fiscal 2025 10-K, so check live data before acting on any of them. Two adjustments matter more here than at most companies: trailing GAAP earnings are not usable because the founders advisory remeasurement moves with the share price, so a rising stock mechanically manufactures a larger loss, and a trailing revenue or EBITDA multiple understates seasonality because Q3 alone can carry more revenue than the two adjacent quarters combined. Consensus has fiscal 2026 revenue near ~$881.5 million and EPS near ~$1.55, rising to ~$995.5 million and ~$1.83 in 2027, which embeds both a full year of Medical Manufacturing Technologies and the start of the DLA foam ramp.

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); PRM shows revenue (ttm) ~$757.1 million trailing twelve months (up ~24%); fiscal 2025 net sales ~$652.9 million (up ~16%); first half 2026 ~$338.9 million (up ~44%), split Fire Safety ~$174.5 million and Specialty Products ~$164.4 million, earnings (gaap) Trailing net loss ~$339.6 million; Q2 2026 net loss ~$181.6 million (~-$1.11 per diluted share) versus ~$32.2 million a year earlier; fiscal 2025 net loss ~$206.4 million (~-$1.37). The swing is driven by ~$266.3 million of founders advisory fee expense in Q2 2026 alone, adjusted profitability Q2 2026 adjusted EBITDA ~$105.6 million (up ~16%) and adjusted EPS ~$0.35 (versus ~$0.39 and below the ~$0.42 consensus); first half adjusted EBITDA ~$146.7 million (up ~34%); fiscal 2025 adjusted EBITDA ~$331.7 million, implying roughly ~$369 million trailing, seasonality Quarterly net sales ran ~$102.8 million (Q4 2025), ~$125.1 million (Q1 2026), ~$213.8 million (Q2 2026) and ~$315.4 million in the peak Q3 2025, so any trailing-twelve-month multiple mixes one fire-season quarter with three quiet ones.

BRK-B and PRM 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 PRM exposure against your real portfolio. It is not an investment adviser.