Innoviva, Inc. (INVA) stock intrinsic value fair value estimate & owner earnings analysis

Innoviva earns most of its cash today from royalties GSK pays on two established inhaled respiratory medicines, Relvar/Breo Ellipta and Anoro Ellipta. Innoviva bears no manufacturing or selling cost on this stream; GSK does all of the commercial work. Starting in 2022, Innoviva began redeploying that royalty cash into a second, wholly-owned business: a small portfolio of hospital-focused infectious-disease and critical-care drugs (Giapreza, Xacduro, Xerava, Zevtera, and the newly approved Nuzolvence), built mainly through the 2022 acquisition of La Jolla Pharmaceutical and subsequent licensing deals. Zevtera launched in the third quarter of 2025 and Nuzolvence was only approved in December 2025, so neither has a full year of sales in the results yet. We measure the cash the business actually generates for owners as operating cash flow after removing the swings from working capital, treating stock-based compensation as a real cost, and subtracting the modest cash needed to maintain the business (Innoviva owns almost no physical plant, so this is minor). Looking at 2022 through 2025 -- the years since the hospital-products business was assembled -- that figure has run between about $1.84 and $2.56 per share, with a midpoint near $2.23, and that midpoint is what we build this valuation from. We did not anchor on 2021's $4.02 per share, which reflected the prior, pure-royalty version of the company after a large one-time share buyback, not the business as it exists today. One accounting item worth flagging in plain terms: Innoviva's reported net income has swung wildly -- over $270 million in 2025, just $23 million in 2024 -- mostly from non-cash mark-to-market changes on equity stakes it holds in companies like Armata Pharmaceuticals, plus a one-time $267 million non-cash gain in 2022 from a portfolio transaction. None of that reaches shareholders as cash, so this valuation is built entirely from actual cash flow rather than the net income line, which we think gives a steadier and more honest read on the business. In the most recently completed year, owner earnings per share actually fell about 3% (from $2.56 to $2.48) even as total owner earnings grew nearly 11%, because the share count grew about 14% on financing tied to the newer product launches. Our base case still assumes modest 3% growth in year one rather than a continued decline, because Zevtera and Nuzolvence only began contributing in the second half of 2025 and are not yet reflected at a full run rate -- a specific, dated reason to expect growth to turn positive, not simply optimism. If that ramp disappoints, or the dilution continues, our estimate would prove too high. In our base case, the GSK royalty stream keeps growing at a low single-digit pace for several more years as the underlying respiratory drugs continue gaining volume, while the newer hospital drugs ramp at a typical, unspectacular pace before both slow later in our ten-year outlook. Beyond that window, we treat the GSK royalty portion -- tied to patents on drugs approved roughly a decade ago -- as a wasting asset that fades out over the following decade, while we treat the hospital-products platform as sustainable near its then-current level, on the view that Innoviva will keep recycling royalty cash into new hospital drugs the way it already has five times since 2022. On these assumptions, we estimate the shares are worth roughly $38. Our bear case (roughly a one-in-ten downside outcome) assumes GSK's respiratory franchise loses momentum faster than expected -- for instance if newer inhaled therapies take share within GSK's own portfolio -- while Zevtera and Nuzolvence disappoint on hospital-formulary adoption, and the company keeps issuing shares to fund growth rather than returning to the buybacks it used in 2021. Under this combination, owner earnings per share would decline for several years rather than grow, and we would expect both the royalty stream and the newer products to fade faster and without full replacement. That scenario is worth roughly $20 per share. Our bull case (roughly a one-in-ten upside outcome) assumes Zevtera and Nuzolvence ramp successfully as they establish themselves in hospitals, the GSK royalty keeps growing modestly with no near-term generic threat, and management returns to the buyback discipline it showed in 2021 instead of financing growth with new shares. That scenario is worth roughly $45 per share. Because the gap between our bear and base cases is fairly wide -- reflecting real risk that both the GSK royalty income and the young hospital-products business could underperform -- the margin-of-safety price is set meaningfully below our estimate of fair value, around $26 per share. A price closer to our full estimate of value would depend on Zevtera and Nuzolvence gaining visible hospital traction through 2026 without further share issuance.