RIGEL PHARMACEUTICALS INC (RIGL) stock intrinsic value fair value estimate & owner earnings analysis

Rigel Pharmaceuticals is a commercial-stage biopharmaceutical company with three approved products: TAVALISSE (fostamatinib), an oral treatment for chronic immune thrombocytopenia approved in 2018; REZLIDHIA (olutasidenib), approved in December 2022 for relapsed/refractory acute myeloid leukemia in patients with an IDH1 mutation; and GAVRETO (pralsetinib), a treatment for RET fusion-positive lung and thyroid cancers that Rigel licensed from Blueprint Medicines in September 2023 for $15 million upfront plus royalties. The business has been transformed over the past three years. In 2022 the company was still absorbing the cost of launching REZLIDHIA and its cash flow was negative. By 2024 all three products were contributing, and in 2025 the company generated meaningfully positive cash flow for the first time in its history, with all three products posting strong sales growth (TAVALISSE +52%, REZLIDHIA +35%, GAVRETO +146% off a partial prior-year base). Because the current three-product business only fully came together in the past two to three years, we anchored our estimate of the company's normalized owner earnings on 2023-2025 results rather than the loss-making years that preceded the REZLIDHIA and GAVRETO additions - those earlier years describe a different, earlier-stage company. Even within that recent window results have swung widely: a loss in 2023 (mid-transition, with GAVRETO contributing only a partial year), a modest profit in 2024, and a much larger profit in 2025. We used the middle of those three years as our anchor, which is a more conservative reading than simply extrapolating 2025's strong result. We'd also note that the most recent six months of results (through June 2026) showed revenue and cash generation below the same period a year earlier - a reminder that this business's growth has not been a straight line, and we've built that caution into our near-term assumptions rather than assuming 2025's pace continues. Our base case assumes modest, uneven growth over the next decade: REZLIDHIA, still early in its launch, continues to gain patients; TAVALISSE holds its base; and GAVRETO faces increasing competitive pressure from Eli Lilly's Retevmo, the market leader in RET fusion-positive lung cancer, compounded by GAVRETO's orphan-drug exclusivity expiring in September 2027 and its earliest patents beginning to expire as soon as 2026. We assume GAVRETO's contribution fades to roughly nothing by the early 2030s. Beyond the ten-year forecast, we assume REZLIDHIA's patent protection (which runs into the mid-to-late 2030s) also fades over time, leaving TAVALISSE - protected into 2046 - as the durable core of the business at a lower, steady level. On this basis we estimate the shares are worth roughly $12.40 today. Our bear case (roughly a one-in-ten downside outcome) assumes the recent softness in results is the start of a real reversal rather than a pause: GAVRETO's sales decline as competition and exclusivity loss bite, REZLIDHIA's launch plateaus below expectations (a common outcome for newly launched specialty drugs), and TAVALISSE's growth stalls. On that path we estimate the shares are worth roughly $7.55. Our bull case (roughly a one-in-ten upside outcome) assumes the softness seen in early 2026 proves temporary, REZLIDHIA continues to gain meaningful share, TAVALISSE's real underlying demand growth continues for several more years, and GAVRETO holds up better than expected against competition. On that path we estimate the shares are worth roughly $16.90. One accounting note: in calculating owner earnings we started from operating cash flow and backed out the swings in working capital (receivables, inventory and prepaid items), stock-based compensation, and capital spending (which is immaterial for this asset-light company). We did not separately add back depreciation or the amortization tied to the acquired GAVRETO license, because operating cash flow already reflects those non-cash charges; instead, because GAVRETO is a wasting asset with a dated expiration, we built its eventual decline directly into the growth assumptions in each case rather than assuming it persists at today's level indefinitely. We also did not subtract Rigel's modest term-loan debt from these values, since owner earnings is already calculated after the cash interest the company pays on that debt. Given the meaningful gap between our bear and base cases, we applied a margin of safety of roughly 25% to our base-case estimate, which puts the margin-of-safety price at approximately $9.26 per share.