Korro Bio, Inc. (KRRO)
KRRO moved a median of +0.32% 30 minutes after news, and -0.59% by the close. How KRRO actually reacts to news — the realized, point-in-time move the market made, measured across 306 labeled events over the last three years with zero look-ahead.
KRRO’s median reaction, across the day.
| Horizon | Median | % positive | Events |
|---|---|---|---|
| 5-min | 0.00% | 42% | 292 |
| 30-min | +0.32% | 53% | 302 |
| 60-min | +0.35% | 52% | 304 |
| to close | -0.59% | 46% | 300 |
| Middle 50% of KRRO reactions | -1.24% to +2.41% |
|---|---|
| Median reaction (30-min) | +0.32% |
| Measured reactions | 306 |
Half of all Korro Bio, Inc. news events land between -1.24% and +2.41% at 30 minutes.
Reaction stats as of 2026-09-21. Newest measured event . Reaction = percent move vs. the price at the news timestamp.
How KRRO reacts, by analyst action.
| Event | Events | Median 30-min | % positive | Median to close |
|---|---|---|---|---|
| Analyst upgrades | 23 | -2.16% | 13% | -3.36% |
| Analyst downgrades | 19 | -5.08% | 11% | +5.20% |
| Coverage initiations | 39 | 0.00% | 44% | -2.53% |
| Rating reiterations | 53 | -0.34% | 45% | +0.06% |
Last 3 years, pulled 2026-09-21. Reaction = percent move vs. the price at the news timestamp. Counts and medians only. The same measurement runs across every name in the dataset. 2 further classes were observed with fewer than 10 measured events and are not published. See how KRRO ranks against every other measured name →
That’s how KRRO usually reacts — get an email when it moves on news →Email me when KRRO moves on news.
One email per qualifying move — the headline, the measured reaction, and how it compares to KRRO's baseline. Nothing else.
Recent KRRO events, each with its measured reaction.
| Date | Headline | Event | Source | 5-min | To close |
|---|---|---|---|---|---|
| Korro Bio Reports Inducement Grants Under Nasdaq Listing Rule 5635(c)(4) | Press release | GlobeNewswire | — | — | |
| Form 8-K Korro Bio, Inc. For: Oct 05 | SEC filing · Form 8-K | SEC EDGAR | +0.10% | -4.31% | |
| Korro Announces First Cohort Dosed in Phase 1/2 Clinical Trial (ANCHOR) for KRRO-121 | Press release | GlobeNewswire | +0.10% | -4.31% | |
| Korro Bio Reports Inducement Grant Under Nasdaq Listing Rule 5635(c)(4) | Press release | GlobeNewswire | +2.80% | +2.13% | |
| Korro to Participate in Upcoming Investor Conferences | Press release | GlobeNewswire | -0.40% | -2.64% | |
| Form 8-K Korro Bio, Inc. For: Aug 19 | SEC filing · Form 8-K | SEC EDGAR | -0.87% | -5.88% | |
| Korro Bio Reports Inducement Grant Under Nasdaq Listing Rule 5635(c)(4) | Press release | GlobeNewswire | +0.00% | +0.23% | |
| Form 10-Q Korro Bio, Inc. For: Jun 30 | SEC filing · Form 10-Q | SEC EDGAR | +0.00% | +5.39% | |
| Form 8-K Korro Bio, Inc. For: Aug 05 | SEC filing · Form 8-K | SEC EDGAR | +0.00% | +5.39% | |
| Korro Reports Second Quarter 2026 Financial Results and Provides Corporate Update | Press release | GlobeNewswire | +0.00% | +5.39% | |
| Korro Bio Reports Inducement Grants Under Nasdaq Listing Rule 5635(c)(4) | Press release | GlobeNewswire | -2.15% | -6.38% | |
| Form 8-K Korro Bio, Inc. For: Jun 10 | SEC filing · Form 8-K | SEC EDGAR | +8.55% | +10.26% | |
| Korro to Present at the 2026 Jefferies Global Healthcare Conference | Press release | GlobeNewswire | +1.63% | +11.87% | |
| Form 8-K Korro Bio, Inc. For: May 19 | SEC filing · Form 8-K | SEC EDGAR | -2.22% | -7.76% | |
| Korro Selects KRRO-111 as Development Candidate for the Potential Treatment of Alpha-1 Antitrypsin Deficiency (AATD) | Press release | GlobeNewswire | -2.22% | -7.76% | |
| Korro Bio Reports Inducement Grant Under Nasdaq Listing Rule 5635(c)(4) | Press release | GlobeNewswire | +4.09% | -3.02% | |
| Form 10-Q Korro Bio, Inc. For: Mar 31 | SEC filing · Form 10-Q | SEC EDGAR | +1.89% | -0.85% | |
| Form 8-K Korro Bio, Inc. For: May 07 | SEC filing · Form 8-K | SEC EDGAR | +1.89% | -0.85% | |
| Korro Reports First Quarter 2026 Financial Results and Provides Corporate Update | Press release | GlobeNewswire | +1.89% | -0.85% | |
| Korro to Participate in Upcoming Investor Conferences | Press release | GlobeNewswire | +0.00% | +4.87% | |
| Form ARS Korro Bio, Inc. For: Dec 31 | SEC filing · Form ARS | SEC EDGAR | -0.07% | -1.53% | |
| Form DEF 14A Korro Bio, Inc. For: Jun 10 | SEC filing · Form DEF | SEC EDGAR | -0.07% | -1.53% | |
| Form DEFA14A Korro Bio, Inc. | SEC filing · Form DEFA14A | SEC EDGAR | -0.07% | -1.53% | |
| Korro Announces Oral and Poster Presentations at Upcoming Scientific Conferences | Press release | GlobeNewswire | — | -0.81% | |
| Korro Bio Reports Inducement Grant Under Nasdaq Listing Rule 5635(c)(4) | Press release | GlobeNewswire | +0.40% | +8.48% | |
| Form EFFECT Korro Bio, Inc. | SEC filing · Form EFFECT | SEC EDGAR | +0.00% | +2.46% | |
| Form S-3 Korro Bio, Inc. | SEC filing · Form S-3 | SEC EDGAR | +0.04% | -4.76% | |
| Form 10-K Korro Bio, Inc. For: Dec 31 | SEC filing · Form 10-K | SEC EDGAR | +5.33% | -5.33% | |
| Form 8-K Korro Bio, Inc. For: Mar 12 | SEC filing · Form 8-K | SEC EDGAR | +5.33% | -5.33% | |
| Korro Reports Fourth Quarter and Full Year 2025 Financial Results and Provides Corporate Update | Press release | GlobeNewswire | +5.33% | -5.33% | |
| Form 8-K Korro Bio, Inc. For: Mar 09 | SEC filing · Form 8-K | SEC EDGAR | +4.25% | +0.41% | |
| Korro Announces Oversubscribed $85 Million Private Placement | Press release | GlobeNewswire | +4.25% | +0.41% | |
| Korro to Present at the TD Cowen 46th Annual Health Care Conference | Press release | GlobeNewswire | +0.00% | +0.25% | |
| Form 8-K Korro Bio, Inc. For: Jan 27 | SEC filing · Form 8-K | SEC EDGAR | +5.29% | +0.37% | |
| Form S-8 Korro Bio, Inc. | SEC filing · Form S-8 | SEC EDGAR | +7.14% | +2.36% | |
| Korro to Host Virtual Analyst Day on January 27, 2026 | Press release | GlobeNewswire | -2.12% | +0.94% | |
| Form 8-K Korro Bio, Inc. For: Jan 15 | SEC filing · Form 8-K | SEC EDGAR | -1.92% | -0.79% | |
| Korro to Present at the 44th Annual J.P. Morgan Healthcare Conference | Press release | GlobeNewswire | +1.19% | +8.54% | |
| Form 8-K Korro Bio, Inc. For: Dec 15 | SEC filing · Form 8-K | SEC EDGAR | +0.14% | +0.77% | |
| Form 10-Q Korro Bio, Inc. For: Sep 30 | SEC filing · Form 10-Q | SEC EDGAR | -2.72% | — | |
| Form 8-K Korro Bio, Inc. For: Nov 07 | SEC filing · Form 8-K | SEC EDGAR | -2.72% | — | |
| Korro Reports Third Quarter Financial Results, Provides Updates on KRRO-110 in Alpha-1 Antitrypsin Deficiency and Additional Pipeline Programs | Press release | GlobeNewswire | -2.72% | — | |
| Form 8-K Korro Bio, Inc. For: Oct 07 | SEC filing · Form 8-K | SEC EDGAR | +1.98% | +1.64% | |
| Korro to Participate in Upcoming Investor and Scientific Conferences | Press release | GlobeNewswire | -1.32% | +18.39% | |
| Form 10-Q Korro Bio, Inc. For: Jun 30 | SEC filing · Form 10-Q | SEC EDGAR | — | — | |
| Form 8-K Korro Bio, Inc. For: Aug 12 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Korro Reports Second Quarter 2025 Financial Results and Provides Business Updates | Press release | GlobeNewswire | — | — | |
| Korro Receives European Medicines Agency Orphan Drug Designation for KRRO-110 | Press release | GlobeNewswire | +1.68% | -2.41% | |
| Form 8-K/A Korro Bio, Inc. For: Jun 11 | SEC filing · Form 8-K | SEC EDGAR | +0.00% | -2.37% | |
| Form 8-K Korro Bio, Inc. For: Jun 11 | SEC filing · Form 8-K | SEC EDGAR | -0.41% | -3.65% |
Each reaction is the move the market actually made, measured from the news timestamp. Headlines link through to the KRRO section they belong to.
Where else KRRO is measured.
KRRO earnings → · Analyst actions → · SEC filings →
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How the numbers are made.
How is Korro Bio, Inc.'s median reaction calculated?
Every labeled KRRO news event is measured from its own timestamp: the last trade before the news is the base price, and the move is read at fixed horizons — 30 minutes of trading, then the close. The median across 306 events is what this page reports. Point-in-time, zero look-ahead: no event borrows information from a later one.
What counts as a positive reaction?
Any event whose price move is above zero at the horizon, relative to the last trade before the news timestamp. 53% of KRRO's measured events are up at 30 minutes; the rest close the window flat or negative.
How often is this page updated?
The news table refreshes automatically as new events are labeled and priced. The reaction medians are re-pulled in batches from the dataset — the figures here are as of 2026-09-21.
Does KRRO's past reaction predict its next one?
No. These are realized facts about past events, not forecasts. They describe a distribution — they say nothing certain about any future move.