TREX CO INC (TREX) stock intrinsic value fair value estimate & owner earnings analysis

Trex Company is the largest North American manufacturer of wood-alternative composite decking and railing, made from reclaimed wood fiber and recycled plastic film. It sells almost entirely through Home Depot, Lowe's, and a network of building-products distributors; in 2025 just three customers accounted for roughly 73% of net sales. Over the past several years the company has undertaken an unusually large capacity build-out, culminating in a new plant in Arkansas, roughly quadrupling production capacity from pre-pandemic levels. Reported cash flow has swung more than the underlying business has, mainly because of this build-out and changes in how much inventory Trex and its retail partners are carrying. Operating cash flow fell sharply in 2024 even though net income rose, because the company intentionally built inventory ahead of its 2025 early-order program and a new product launch, not because demand weakened. We adjusted for these working-capital swings, non-cash stock compensation, and the portion of capital spending tied to genuinely new capacity to get a normalized owner-earnings figure. We also added back a one-time, non-cash $54 million write-down the company took in 2021 on a small, unrelated commercial railing business it fully sold at the end of 2022 - a write-down like that is a sunk cost from a past acquisition, not an ongoing charge. Using the four most recent fiscal years (2022-2025) - since that non-core business was sold, spanning both a soft patch in 2022-2023 and a partial recovery in 2024-2025 - normalized owner earnings have run at a median of roughly $1.99 per share. Our base case assumes the margin pressure Trex reported in 2025 (gross margin fell to about 39% from roughly 44% in 2024) is mostly temporary, tied to Arkansas plant start-up costs, tariffs and a one-time product-line changeover, partly offset by a January 2025 price increase. We assume owner earnings grow modestly in 2026 as the plant matures, then grow at a mid-single-digit pace before slowing toward a low, sustained rate. On these assumptions we estimate the shares are worth roughly $48.70 today. A substantial share of that value depends on what Trex earns well beyond the next ten years, since these are physical manufacturing assets rather than an expiring patent, but that also means a large part of the estimate rests on a long-run growth assumption. Our bear case reflects Trex's biggest structural risk: heavy reliance on just two or three retail and distribution partners. We assume one of those partners meaningfully reduces shelf space or orders, combined with the new Arkansas capacity staying under-utilized longer than hoped, keeping margins depressed. Under this scenario we estimate the shares would be worth about $28.60. Our bull case assumes the Arkansas ramp-up goes smoothly, gross margins recover toward or above the 2024 level, and composite decking keeps taking share from wood, supported by continued share buybacks. Under this scenario we estimate the shares could be worth about $65.00. Weighing that range against how much of the downside is cushioned by the durability of the underlying business, the margin-of-safety price is around $35.50. Two items we could not fully reconcile from the filings: the split between new-capacity spending and ordinary sustaining spending is only clearly broken out by Trex starting in 2022, so the same split for 2016-2021 relies on an estimate; and a modest restatement of 2023-2024 net income and taxes in the most recent filing was not separately explained by the company.