OLN vs WLK: How Olin Corporation and Westlake Corporation Compare (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: OLN 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. OLN and WLK 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 OLN and WLK 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.

Olin Corporation, incorporated in Virginia in 1892 and headquartered in Clayton, Missouri, is a vertically integrated global manufacturer and distributor of chemical products and the leading U.S. manufacturer of ammunition. Its largest business, Chlor Alkali Products and Vinyls, produces chlorine, caustic soda, ethylene dichloride (EDC), vinyl chloride monomer, chlorinated organics, hydrochloric acid, hydrogen, and bleach, and represented about 54% of 2025 sales. Olin is one of the world's largest chlor alkali producers, with roughly a fifth of North American capacity. The Epoxy segment (about 20% of 2025 sales) makes epoxy resins and precursors such as allyl chloride, epichlorohydrin, and phenol and acetone aromatics. The Winchester segment (about 26% of sales) produces sporting, law-enforcement, and small-caliber military ammunition, reloading components, and clay targets, and in April 2025 completed the acquisition of the small caliber ammunition assets of AMMO, Inc., adding a 185,000 square foot plant in Manitowoc, Wisconsin.

Full OLN guide

Westlake Corporation runs two segments. Performance and Essential Materials (PEM) is the commodity side: chlor-alkali and vinyls (chlorine, caustic soda, PVC resin), olefins (ethylene, polyethylene, styrene), plus epoxy and specialty chemicals sold into packaging, pipe, coatings and wind blades. Housing and Infrastructure Products (HIP) is the downstream side: PVC pipe and fittings, siding, trim, windows, decking and roofing sold to builders, distributors and big-box retail, much of it built on resin Westlake makes itself. That vertical integration is the whole design idea. The company captures margin at both the molecule and the finished-product stage, which softens (though never removes) the swing when resin prices move. The Chao family controls roughly 72% of the shares through family entities, so public holders own a minority float in a founder-controlled company.

Full WLK guide

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

• OLN drivers: Pending Merger of Equals with Huntsman; Chlor Alkali Pricing and ECU Recovery.
• WLK drivers: The three-pillar self-help program; Vinyls and olefins pricing off a cyclical trough.

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: Olin's earnings are highly cyclical and commodity-priced, so weak chlorine, caustic soda, EDC, and epoxy pricing can push results to a loss quickly, as the first quarter 2026 net loss of about $83 million showed. For WLK, the single biggest risk is that Q2 2026 was a price spike, not a floor: PEM's margin expansion was driven substantially by oil prices elevated on Middle East conflict, and if crude retreats while global PVC and polyethylene capacity stays long, the spread compresses fast.

Pick OLN if you believe its drivers more; WLK 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 OLN and WLK guides.

OLN. Olin's trailing price-to-earnings ratio is negative because the trailing twelve months include losses, so investors lean on normalized mid-cycle earnings, EV/EBITDA, and the pending Huntsman exchange ratio instead of reported P/E. The share price near the low $20s and a market capitalization around $2.3 billion reflect a cyclical trough in chlor alkali and epoxy pricing plus deal uncertainty. These figures are approximate and move with commodity prices and merger developments.

WLK. Trailing earnings are negative because of the 2025 write-downs, so the trailing P/E is meaningless and the market is pricing off forward estimates at roughly 22 times, plus about 4 times EV to a normalizing EBITDA run rate if the second-quarter pace held. The share count is about 128 million and the stock trades near $80 against a 52-week range of roughly $56 to $124, so it has bounced hard off the low without recovering the high. Cyclical chemical names look expensive on trough earnings and cheap on peak earnings, which is exactly the inversion to keep in mind here.

Headline figures (approximate, July 2026): OLN shows revenue (full year 2025) ~$6.7 billion, revenue (q1 2026) ~$1.58 billion (down ~4% year over year), net income (q1 2026) ~-$83 million (loss), ~-$0.73 per diluted share, adjusted ebitda (q1 2026) ~$86 million (down from ~$186 million a year earlier); WLK shows revenue (ttm) ~$11.3B, q2 2026 net sales / ebitda ~$3.27B / ~$679M, q2 2026 eps (diluted) ~$2.01, net income (ttm) ~-$1.2B (2025 impairments).

OLN and WLK 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 OLN and WLK exposure against your real portfolio. It is not an investment adviser.