BRK-B vs OC: 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: OC 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 OC 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 OC 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

Owens Corning sells three things that go into houses: asphalt roofing shingles, insulation, and doors. Founded in 1938 and headquartered in Toledo, Ohio, it files with the SEC under the plain name Owens Corning, with no Inc. or Corp. attached. Roofing is the biggest and most profitable segment, at ~$1,313 million of second-quarter 2026 sales on a ~34% EBITDA margin, and most of that volume is replacement work: shingles age, storms strip them, and the homeowner reroofs whether or not housing starts are healthy. Insulation, ~$971 million in the quarter, spans fiberglass batts, loose fill, foam sheathing and European stone wool from the Paroc business, and reaches non-residential jobs as well as homes. Doors, ~$513 million, is the Masonite business bought in May 2024. On April 30, 2026 the company closed the sale of its global glass reinforcements operation, retiring the last of the old Composites segment.

Full OC 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.
• OC drivers: Roofing runs on replacement, not on housing starts; The portfolio was deliberately narrowed to residential.

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 OC, roofing demand is weather-dependent, so a mild storm season removes volume from the segment that generates most of the profit, and the company already warned that second-quarter distributor stocking borrows from the third quarter.

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; OC 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 OC 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.

OC. The headline loss is an accounting artifact of two decisions rather than a description of current trading: the glass reinforcements sale was carried through discontinued operations at a pre-tax loss of ~$175 million for the first half, and Doors took ~$1,135 million of goodwill impairment plus ~$39 million of tradename impairment during 2025. Continuing operations produced ~$660 million of adjusted EBITDA on a ~24% margin in the quarter. Third-quarter guidance calls for ~$2.6 billion to ~$2.7 billion of revenue at a ~20% to ~22% adjusted EBITDA margin, and the quarterly dividend annualizes to roughly ~$3.16 per share, about a ~2.1% yield at recent prices.

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); OC shows revenue (ttm, continuing operations) ~$9.85 billion, q2 2026 net sales ~$2.76 billion, roughly flat vs ~$2.75 billion, q2 2026 adjusted eps (continuing ops) ~$3.93 vs ~$4.21 a year earlier, net loss (ttm, gaap, incl. discontinued ops) ~-$671 million, or ~-$8.23 per share.

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