KRRO Stock: Insider Activity, Filings & Research

Korro Bio, Inc. (KRRO) — Drillr’s hub for KRRO insider activity, SEC filings, earnings signals and AI research. Over the trailing 3 months, KRRO insiders filed 19 open-market buys and 3 sales (SEC Form 4).

Sentiment

98/100

Buys (3m)

Sells (3m)

Net (3m)

$20.5M

Insiders buyingCluster buying

Insider trades by month Buys Sells

Apr

Oct

Nov

Mar

Apr

Jun

Context3-month price -0.6%Institutions accumulating (13F)

Date	Insider	Type	Shares	Price
Jun 2, 2026	Aiyar Ramdirector, officer: President and CEO	Sell	15,152	$12.98
Jun 1, 2026	FORMELA JEAN FRANCOISdirector	Sell	2,441	$13.95
Jun 1, 2026	FORMELA JEAN FRANCOISdirector	Sell	419	$13.95
May 28, 2026	Aiyar Ramdirector, officer: President and CEO	Grant	50,000	$12.33
Apr 2, 2026	Lynx1 Capital Management LP10 percent owner	Buy	520	$10.60
Mar 12, 2026	Yang Rick10 percent owner	Buy	207,100	$11.11
Mar 12, 2026	Chang Carmen10 percent owner	Buy	207,100	$11.11
Mar 12, 2026	New Enterprise Associates 17, L.P.10 percent owner	Buy	207,100	$11.11
Mar 12, 2026	SANDELL SCOTT D10 percent owner	Buy	242,945	$0.00
Mar 12, 2026	SANDELL SCOTT D10 percent owner	Buy	207,100	$11.11
Mar 12, 2026	Yang Rick10 percent owner	Buy	242,945	$0.00
Mar 12, 2026	Makhzoumi Mohamad10 percent owner	Buy	242,945	$0.00
Mar 12, 2026	Makhzoumi Mohamad10 percent owner	Buy	207,100	$11.11
Mar 12, 2026	Mathers Edward T10 percent owner	Buy	242,945	$0.00
Mar 12, 2026	Mathers Edward T10 percent owner	Buy	207,100	$11.11

Source: KRRO SEC Form 4 filings, latest Jun 2, 2026. For informational purposes only — not investment advice.

Overview

Korro Bio, Inc. (NASDAQ:KRRO) is a biopharmaceutical company founded in 2018 and headquartered in Cambridge, Massachusetts. The company went public in October 2019 and specializes in developing genetic medicines through RNA editing technology. Korro Bio focuses on creating treatments for both rare genetic diseases and more common conditions by correcting disease-causing mutations at the RNA level rather than permanently altering DNA. The company is currently in the clinical development stage with multiple programs targeting various therapeutic areas.

Business

Korro Bio operates in the biotechnology sector, specifically in the emerging field of RNA editing therapeutics. Unlike traditional gene therapy that permanently modifies DNA, RNA editing allows for temporary, reversible changes to genetic instructions by targeting RNA molecules - the intermediary messengers that carry genetic information from DNA to produce proteins. The company's core technology platform is called ADAR-mediated RNA editing, which harnesses naturally occurring enzymes called ADARs (Adenosine Deaminases Acting on RNA) to make precise changes to RNA sequences. This approach can potentially correct disease-causing mutations by converting adenosine to inosine in RNA, which cells read as guanosine, effectively changing the genetic message and potentially restoring normal protein function. Korro Bio's pipeline includes programs targeting several therapeutic areas. Their lead programs focus on ophthalmology, particularly inherited retinal diseases like Leber Congenital Amaurosis, which causes childhood blindness. The company is also developing treatments for hepatic diseases including Alpha-1 Antitrypsin Deficiency, a genetic condition that can cause liver and lung problems. Additionally, they have programs in central nervous system disorders and are exploring applications in more prevalent conditions like cardiovascular disease. The company generates minimal revenue currently, with approximately $2.3 million in revenue for 2024, likely from research collaborations or licensing agreements. As a clinical-stage biotech company, Korro Bio is primarily focused on advancing its pipeline through clinical trials rather than commercial product sales.

Revenue model

As a clinical-stage biopharmaceutical company, Korro Bio currently operates on a research and development model with limited revenue generation. The company's primary revenue sources include research collaboration agreements, licensing deals, and potentially grant funding, which generated approximately $2.3 million in 2024. The company's future business model will likely center on product sales and licensing once its RNA editing therapies reach commercialization. For rare disease treatments, biotech companies typically employ a high-price, low-volume strategy due to small patient populations and significant development costs. The company may also pursue partnership and licensing agreements with larger pharmaceutical companies to co-develop or commercialize their therapies, which could provide upfront payments, milestone payments, and royalties. Several factors could significantly impact Korro Bio's future margins and profitability. Regulatory success is paramount - positive clinical trial results and FDA approvals would dramatically increase the company's value and revenue potential. The competitive landscape in RNA editing, including companies like Wave Life Sciences and other gene therapy developers, could affect pricing power and market share. Manufacturing costs for RNA editing therapies may be substantial, though potentially lower than some gene therapies since they don't require permanent genetic modification. The company's ability to expand beyond rare diseases into larger patient populations would significantly improve revenue potential. Additionally, intellectual property protection and the ability to maintain technological advantages in ADAR-mediated editing will be crucial for maintaining competitive positioning and pricing power in this emerging therapeutic area.

Competitive moat

Korro Bio's competitive moat is currently moderate but developing, typical of early-stage biotech companies in emerging therapeutic areas. The company's primary moat lies in its proprietary ADAR-mediated RNA editing platform and accumulated expertise in this specific approach to genetic medicine. RNA editing is a relatively new field with few established players, giving Korro Bio potential first-mover advantages in certain therapeutic applications. The company's intellectual property portfolio around ADAR-mediated editing techniques provides some protection, though the durability of this moat depends on the strength and breadth of their patent claims. Their clinical data and regulatory experience in advancing RNA editing therapies through human trials creates valuable know-how that competitors would need time to replicate. However, the moat faces several challenges. The RNA editing field is attracting significant investment and competition from both startups and established pharmaceutical companies. Wave Life Sciences and other companies are pursuing similar RNA editing approaches, while broader gene therapy and genetic medicine companies like Sarepta Therapeutics and Alnylam Pharmaceuticals have resources and expertise that could be redirected toward RNA editing. The fundamental ADAR enzymes that Korro Bio's platform relies on are naturally occurring, limiting the ability to create truly proprietary biological mechanisms. The company's moat will ultimately depend on clinical execution and data generation. Successful clinical trials demonstrating safety and efficacy would significantly strengthen their competitive position, while failures could erode their advantages. The ability to expand their platform across multiple therapeutic areas and establish partnerships with larger pharmaceutical companies will be crucial for building a sustainable competitive advantage in this rapidly evolving field.

Risks & safety

Korro Bio presents a moderate margin of safety typical of clinical-stage biotech companies, with strong liquidity but ongoing cash burn concerns. • Cash position: $64.1 million in cash and short-term investments as of Q1 2025, providing operational runway • Burn rate: Quarterly cash burn of approximately $24.5 million from operations in Q1 2025, suggesting roughly 2.5 years of runway at current spending levels • Debt levels: Moderate debt-to-equity ratio of 0.33, indicating manageable leverage • Liquidity: Strong current ratio of 9.4, indicating excellent short-term liquidity position • Solvency risk: Low immediate solvency risk given cash position, but will need additional funding within 2-3 years • Valuation metrics: Trading at 1.2x book value and negative earnings multiples due to development stage losses • Enterprise value: Negative EV/EBITDA multiple reflects pre-revenue status • Other considerations: Clinical-stage risk remains high with binary outcomes from trial results, but strong balance sheet provides cushion for continued operations and development activities.

Recent development

Based on the available financial data, Korro Bio has been progressing through typical clinical-stage biotech development over the past few years. The company has maintained a consistent R&D focus with quarterly operating losses of approximately $20-24 million, indicating steady investment in their RNA editing platform and clinical programs. A notable development has been the company's ability to generate some collaboration revenue, with $2.3 million reported in 2024 compared to zero revenue in previous years. This suggests the company may have established research partnerships or licensing agreements, which is common for biotech companies seeking to validate their technology and generate non-dilutive funding. The company's cash management has shown improvement, with free cash flow improving from -$78 million in 2024 to -$25 million in Q1 2025, though this may reflect timing of expenditures rather than fundamental changes in burn rate. The maintenance of a strong balance sheet with over $64 million in cash provides the financial foundation needed to advance multiple clinical programs simultaneously. Korro Bio appears to be in a clinical execution phase, focusing on advancing their ADAR-mediated RNA editing programs through human trials. The company's ability to maintain operations while generating initial partnership revenue suggests they are successfully building relationships within the pharmaceutical industry, which could be crucial for future development and commercialization partnerships.

KRRO company profile · for informational purposes only — not investment advice.

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