Climb Bio, Inc. (CLYM) stock intrinsic value fair value estimate & owner earnings analysis

Climb Bio is a clinical-stage biotechnology company with no product revenue. Its lead candidate, budoprutug, is an anti-CD19 antibody in a Phase 2 trial (PrisMN, first patient dosed November 2025) for primary membranous nephropathy, where a small earlier Phase 1b study showed complete remission of proteinuria in three of five patients who completed 48 weeks of follow-up, and in a Phase 1b/2a trial in immune thrombocytopenia (cleared by the FDA in March 2025). The FDA has granted orphan-drug designation for membranous nephropathy. The company owns worldwide rights to budoprutug outside oncology. Because the company earns nothing, its owner earnings are negative: about $(23.0) million in 2024 and $(62.0) million in 2025, or roughly $(0.48) and $(0.91) per diluted share. Owner earnings here means operating cash flow less working-capital swings, stock compensation and maintenance capital spending. Working capital moved little and capital spending was only $186 thousand in 2025. Only 2024 and 2025 are used because they are the years for which we could build a complete and consistent working-capital and capital-spending record. The loss deepened in 2025 (from $(0.48) to $(0.91) per share); the first half of 2026 cash burn of $24.9 million is slightly below the $26.6 million of the first half of 2025, so we assume spending stays near $50 million a year rather than rising. We do not credit any value for budoprutug. It has not completed a Phase 2 trial, and the human data so far in membranous nephropathy are five patients, so no future sales enter any case. What is left is the cash that remains when results force a decision. The company held $160.7 million of cash and marketable securities at the end of 2025 and states this funds operations into 2028. Subtracting the $24.9 million used in the first half of 2026 leaves roughly $136 million, about $1.78 per share on roughly 76 million shares. Each case is that cash less the spending before a stop-or-continue decision. Bear case ($0.37 per share): spending continues at the 2025 pace of about $54 million a year until mid-2028, consistent with the company's own runway, leaving about $28 million. Base case ($0.80): spending of about $50 million a year through the end of 2027, the point at which we assume a stop-or-continue decision is made on the PrisMN and immune thrombocytopenia programs, leaving about $61 million. Bull case ($1.13): the same decision is reached earlier, by mid-2027, after about one year of spending, leaving about $86 million. The company did not sell any shares under its at-the-market program in 2025, so we assume no dilution, but any future equity raise would reduce these per-share values. What could prove this wrong: strong Phase 2 data would make budoprutug worth far more than the cash, and we assign no value to that outcome. Conversely, trial delays or higher costs would burn cash faster. We tested the runway claim against the reported cash-flow figures: 2025 operating cash burn was $54.4 million against $160.7 million of cash, and the first half of 2026 shows no acceleration. The margin-of-safety price is $0.35, a deep discount to the base case, given a single early-stage asset and cash that is spent every quarter.