Korro Bio, Inc. (KRRO) stock intrinsic value fair value estimate & owner earnings analysis

Korro Bio is a Cambridge, Massachusetts biotechnology company developing RNA-editing medicines on its OPERA platform. It has no products for sale and no earnings. Every program is still in the research or preclinical stage. Its earlier clinical program, KRRO-110 for alpha-1 antitrypsin deficiency, has been terminated, and the most advanced program is now KRRO-121 for hyperammonemia, with a regulatory filing planned for the second half of 2026. The only revenue so far has been collaboration revenue from Novo Nordisk: $2.3 million in 2024 and $6.4 million in 2025. That collaboration was paused for 12 months in November 2025, and the company does not expect material revenue from it during the pause. What the business earns. On our measure of owner earnings (operating cash flow, less working-capital swings, less stock compensation, less capital spending), Korro lost about $99.3 million in 2024 (-$11.14 per share) and about $83.0 million in 2025 (-$8.84 per share). In both years we treated all capital spending as ongoing, because the company has no product revenue that capital spending is expanding. We also removed the lease-related cash timing: in 2024 operating cash flow was flattered by an $11.6 million rise in lease liabilities. In 2025 a $30.9 million non-cash write-down ($15.0 million on the lease right-of-use asset and $15.9 million on property and equipment) was added back, as it is not a cash cost. The 2025 loss was 16 percent smaller than in 2024, and we assume no further improvement. Because owner earnings are negative in every year, there is no earnings level to build a valuation on. The value of this company rests on the cash it holds against what it owes. What we credit and what we leave out. At June 30, 2026 the company held $24.9 million of cash and $90.1 million of marketable securities, $115.0 million in total, against total liabilities of $60.2 million. Of those liabilities, $42.2 million is a lease on 50,453 square feet of office and laboratory space at 60 First Street in Cambridge that runs to April 2034. Cash used in operations was $33.1 million in the first half of 2026 (about $66 million a year), $78.6 million in 2025 and $60.1 million in 2024. The company states its cash should last into the second half of 2028. We count the cash and the lease and other bills as real obligations. We assign nothing to the drug pipeline, because every current program is still preclinical, the one program that had reached the clinic (KRRO-110) was terminated, and nothing yet exists that we can point to as producing future earnings. We also assign nothing to the Novo Nordisk agreement's potential payments (up to $115 million of development and regulatory milestones and $140 million of sales milestones for the first target, with similar amounts for a second target if Novo Nordisk chooses one). Those depend on Novo Nordisk choosing to advance the programs and on drugs being approved, and the collaboration is currently paused. The three cases. All values are per share on about 17.6 million diluted shares, which includes shares issued in the March 2026 private placement ($85.0 million raised at $11.11 per share, in part through pre-funded warrants). - Bear, -$0.50 per share: research spending continues at the first-half 2026 pace for another year with nothing to show for it, and the company then shuts down. That leaves about $48.9 million of cash against roughly $39.7 million still owed on the lease and about $18.0 million of other liabilities. The company would owe slightly more than it holds, by roughly $9 million, so shareholders would receive nothing. The termination of KRRO-110 and the 2025 write-down of the lease and equipment are why we treat this as a real possibility. - Base, $1.31 per share: spending continues for about six months, through the planned KRRO-121 filing and the end of the Novo Nordisk pause, and the company then stops. That leaves about $82.0 million of cash against about $40.9 million of remaining lease and $18.0 million of other liabilities, or about $23.0 million for shareholders. - Bull, $3.11 per share: the company keeps its cash and pays off everything it owes today, leaving $54.8 million ($115.0 million less $60.2 million). This is the ceiling of what we can support from the balance sheet; the pipeline adds nothing we can name and verify. Margin-of-safety price. The margin-of-safety price is $0.60 per share, and it applies only once spending is cut toward the level of cash coming in, or Novo Nordisk restarts and reimburses research costs (see the trigger). The margin of safety is large because the bear case leaves nothing for shareholders, the company is burning cash, and any raise of new money dilutes existing holders (shares grew from 9.4 million in early 2025 to 14.7 million by August 2026, plus pre-funded warrants). What would make this estimate wrong. A clinical success for KRRO-121 or the Novo Nordisk programs would be worth far more than this balance-sheet view, and we are deliberately not valuing it because none of it exists yet. The wind-down figures are approximations that treat the lease and other liabilities at their reported balances: a sublease or early exit from the lease would raise the bear and base values, while severance or other shutdown costs would lower them.