Insider · CIK 0001885327
Atlas Venture Opportunity Fund II, L.P.
Files at SION (Sionna Therapeutics, Inc.). First filing -, latest -.
Atlas Venture Opportunity Fund II, L.P. files SEC Form 4 as 10% owner at SION (Sionna Therapeutics, Inc.). No open-market trade is on file; the transactions below are grants, exercises and other rows that carry no view on the price.
A track record needs three past buys with six months of prices behind them; Atlas Venture Opportunity Fund II, L.P. has 0, so none is measured yet.
Signals
This insider’s open-market buys and sells, scored.
Planned sales
Form 144 notices this insider filed before selling restricted or control stock, newest first.
| Filed | Company | Shares | Value | Sale date | Past 3 months |
|---|---|---|---|---|---|
| Sep 14, 2026 | KRRO Korro Bio, Inc. | 6,602 0.04% of outstanding | $91k | Sep 14, 2026 | $4.6M |
| Sep 11, 2026 | KRRO Korro Bio, Inc. | 1,750 0.01% of outstanding | $23k | Sep 11, 2026 | $4.4M |
| Sep 4, 2026 | IRON Disc Medicine, Inc. | 759 0.00% of outstanding | $60k | Sep 4, 2026 | none |
| Sep 3, 2026 | IRON Disc Medicine, Inc. | 2,339 0.01% of outstanding | $187k | Sep 3, 2026 | none |
| Sep 2, 2026 | IRON Disc Medicine, Inc. | 22,099 0.06% of outstanding | $1.7M | Sep 2, 2026 | none |
| Aug 26, 2026 | KRRO Korro Bio, Inc. | 51 0.00% of outstanding | $700 | Aug 26, 2026 | $4.5M |
| Aug 19, 2026 | KRRO Korro Bio, Inc. | 4,884 0.03% of outstanding | $65k | Aug 19, 2026 | $4.1M |
| Aug 14, 2026 | DYN Dyne Therapeutics, Inc. | 478,377 0.26% of outstanding | $12M | Aug 14, 2026 | none |
| Aug 13, 2026 | DYN Dyne Therapeutics, Inc. | 94,415 0.05% of outstanding | $2.5M | Aug 13, 2026 | none |
| Aug 11, 2026 | KRRO Korro Bio, Inc. | 368 0.00% of outstanding | $4,964 | Aug 11, 2026 | $4.0M |
| Jul 7, 2026 | DYN Dyne Therapeutics, Inc. | 77,387 0.05% of outstanding | $1.8M | Jul 7, 2026 | none |
| Jul 6, 2026 | KRRO Korro Bio, Inc. | 8,506 0.06% of outstanding | $119k | Jul 6, 2026 | $3.9M |
| Jul 6, 2026 | DYN Dyne Therapeutics, Inc. | 127,182 0.08% of outstanding | $2.9M | Jul 6, 2026 | none |
| Jul 2, 2026 | KRRO Korro Bio, Inc. | 14,745 0.10% of outstanding | $201k | Jul 2, 2026 | $2.5M |
| Jun 29, 2026 | DYN Dyne Therapeutics, Inc. | 51,756 0.03% of outstanding | $1.1M | Jun 29, 2026 | none |
| Jun 26, 2026 | DYN Dyne Therapeutics, Inc. | 81,903 0.05% of outstanding | $1.7M | Jun 26, 2026 | none |
| Jun 25, 2026 | DYN Dyne Therapeutics, Inc. | 6,382 0.00% of outstanding | $130k | Jun 25, 2026 | none |
| Jun 24, 2026 | DYN Dyne Therapeutics, Inc. | 25,397 0.02% of outstanding | $515k | Jun 24, 2026 | none |
| Jun 24, 2026 | KRRO Korro Bio, Inc. | 7,093 0.05% of outstanding | $97k | Jun 24, 2026 | $1.8M |
| Jun 23, 2026 | KRRO Korro Bio, Inc. | 17,426 0.12% of outstanding | $242k | Jun 23, 2026 | $95k |
| Jun 23, 2026 | DYN Dyne Therapeutics, Inc. | 39,131 0.02% of outstanding | $817k | Jun 23, 2026 | none |
| Jun 22, 2026 | KRRO Korro Bio, Inc. | 3,661 0.03% of outstanding | $48k | Jun 22, 2026 | $40k |
| May 6, 2026 | DYN Dyne Therapeutics, Inc. | 21,926 0.01% of outstanding | $383k | May 6, 2026 | none |
| May 5, 2026 | DYN Dyne Therapeutics, Inc. | 3,056 0.00% of outstanding | $54k | May 5, 2026 | none |
| May 4, 2026 | DYN Dyne Therapeutics, Inc. | 3,136 0.00% of outstanding | $55k | May 4, 2026 | none |
Transactions
Every row this insider has filed, 0 in all, newest first.
Questions about Atlas Venture Opportunity Fund II, L.P.
Answered from the filings on this page, as of the latest one.
Is Atlas Venture Opportunity Fund II, L.P. buying or selling?
Atlas Venture Opportunity Fund II, L.P. has no open-market buy or sell on SEC Form 4; the filings on record are grants, exercises and other transactions.
How did Atlas Venture Opportunity Fund II, L.P.'s past buys perform?
Not measured yet. InsiderTell needs three past buys with six months of prices to publish a track record, and Atlas Venture Opportunity Fund II, L.P. has 0.
Where does Atlas Venture Opportunity Fund II, L.P. file Form 4?
Atlas Venture Opportunity Fund II, L.P. has filed Form 4 at SION (Sionna Therapeutics, Inc.). A Form 4 is required of officers, directors and holders of more than 10% of a share class within two business days of a trade.
Not investment advice. Scores and forward returns are decision support built from public SEC filings and past prices; they describe what happened after comparable filings, not what will happen after this one. Do your own research and size your risk.