UPDATE: Taysha Gene Therapies (TSHA) - Follow the Money, Finally

I have ended three consecutive updates on this name with the same open item: whether RA Capital and RTW stepped up on the $6.00 June follow-on. On June 25 I called the 13F season “the single most diagnostic datapoint for thesis conviction.” On August 3 and again on August 11 I wrote that I still hadn’t gotten it.

I got it today — not from a 13F, but from a Schedule 13G/A that landed this morning. And it answers the question more directly than a 13F would have.

The Position. RA Capital Healthcare Fund directly holds 23,555,648 shares of common stock plus pre-funded warrants exercisable for up to 52,134,718 shares. That’s roughly 75.7 million shares of economic exposure in a company with ~325.8M shares outstanding as of August 11. The implication: On a fully-exercised basis that’s north of 20% of the company — held by one of the most respected science-driven funds in the sector.

The Blocker Is Doing Exactly What I Described in March. Reported beneficial ownership is pinned at 9.99% — 32,886,242 shares — because the Beneficial Ownership Blocker precludes exercise beyond that threshold. In the original deep dive I wrote that RA Capital’s ownership is “artificially capped at 9.99%... their actual economic exposure is significantly higher.” The filing now quantifies “significantly”: the warrant overhang alone is more than twice the reportable stake.

The Timing Matters. The event date is June 30, 2026 — four days after the June 26 offering close and full greenshoe exercise. The share-count math in the filing explicitly includes the 32,500,001 shares issued in the June deal. Why it matters: This is a post-deal snapshot. Whatever RA Capital’s participation was, this is the position they were carrying into the second half.

The Warrant Structure Question, Partially Resolved. On June 25 I flagged that the pre-funded warrant tranche in the offering was only 833,333 warrants against 32.5M common — a ratio of ~2.5%, versus ~27% in the 2023 PIPE — and read that as thin evidence the blocker-constrained holders anchored the book. Today’s filing complicates that read: RA Capital’s warrant stack of 52.1M dwarfs anything sourced from the June deal, meaning the bulk of that exposure was built in prior financings. They didn’t need the June warrant tranche because they were already maxed out against the blocker. The honest correction: the small warrant tranche in June was less diagnostic than I treated it as. RA Capital’s exposure isn’t a function of any single deal — it’s a nine-figure structural position that predates it.