% of shares outstanding is not shown for IREX: this is a fund line, and we hold no cover-page share count for it at any quarter — a fund's shares outstanding move with creations and redemptions rather than with issuance and buybacks, and it is not the SEC cover-page count this percentage is defined against. The figure is withheld rather than computed against a count that does not exist. Holder share counts are shown as filed.
Crowding percentile withheld — no market cap for IREX in the served universe — the cohort is size-matched, and an unmatched percentile would compare a micro-cap register to a mega-cap one.
| # | Holder | Shares | Value | % of shares out | Δ QoQ |
|---|---|---|---|---|---|
| 1 | UBS Group AG | 188,636188,636 | $3M | — | NEW |
| 2 | JANE STREET GROUP, LLC | 20,93820,938 | $363,065 | — | NEW |
| 3 | Scientech Research LLC | 14,47114,471 | $250,927 | — | NEW |
| 4 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 14,43814,438 | $250,355 | — | NEW |
| 5 | CITADEL ADVISORS LLC | 11,74811,748 | $203,710 | — | NEW |
| 6 | Belvedere Trading LLC | 9,8119,811 | $170,123 | — | NEW |
| 7 | Tower Research Capital LLC (TRC) | 5454 | $936 | — | NEW |
Rows rank by the value each filer reported — 13F filers price their own positions, so a holder with fewer shares can rank just above one with more.
| Holder | 2024-Q4 | 2025-Q1 | 2025-Q2 | 2025-Q3 | 2025-Q4 | 2026-Q1 | Latest value |
|---|---|---|---|---|---|---|---|
| UBS Group AG | — | — | — | — | — | 189K | $3M |
| JANE STREET GROUP, LLC | — | — | — | — | — | 21K | $363,065 |
| Scientech Research LLC | — | — | — | — | — | 14K | $250,927 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | — | — | — | — | — | 14K | $250,355 |
| CITADEL ADVISORS LLC | — | — | — | — | — | 12K | $203,710 |
| Belvedere Trading LLC | — | — | — | — | — | 10K | $170,123 |
| Tower Research Capital LLC (TRC) | — | — | — | — | — | 54 | $936 |
Shares reported each quarter by the largest current holders. Green = added vs the prior filing, red = trimmed, grey = roughly held; a dash is a quarter with no 13F on file (a gap is skipped, not read as an exit). 13F is filed up to 45 days after quarter-end. Up to 40 quarters (10 years) available — use the selector above.
Short interest has its own tab now — open SI →
Source: SEC Form 13F — every institution manager (≥ $100M in 13F securities) reporting a long US-listed position, across ~10,250 filers over 10 years of history. 13F is long-only, US-listed, filed up to 45 days after quarter-end.
| Biggest buyers | Δ shares | Δ value | |
|---|---|---|---|
| UBS Group AG | +188,636 | $3M | OPEN |
| JANE STREET GROUP, LLC | +20,938 | $363,065 | OPEN |
| Scientech Research LLC | +14,471 | $250,927 | OPEN |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | +14,438 | $250,355 | OPEN |
| CITADEL ADVISORS LLC | +11,748 | $203,710 | OPEN |
| Biggest sellers | Δ shares | Δ value | |
|---|---|---|---|
| No filer reduced its position this quarter. | |||
The 2025-Q4 register is as-filed in ITS OWN share basis; every count below was rebased into the 2026-Q1 basis (no split in between, factor 1). Dollar figures value the SHARE delta at one price — the 2026-03-31 close — rather than differencing two filings' own reported values, which would mix the quarter's price move into the trade figure.
13Fs disclose LONG US-listed positions only — shorts, most derivatives, bonds and non-US listings are invisible here, and a filer's quarter-over-quarter change is not necessarily a trade (index rebalances, in-kind transfers and entity successions all read as flow).
