% of shares outstanding not shown: this line files 20-F annual reports only — a foreign private issuer whose US listing trades as ADSs (depositary receipts), while its cover-page share count is in ORDINARY shares. The depositary ratio is not in our data. The count we hold for this line is 28,857,673,160 shares (as of 2025-12-31, source dei). Dividing one by the other is wrong by the whole ratio (a 5:1 ADR reads one fifth of the true percentage), so the percentage is withheld rather than served wrong. Holder share counts are shown as filed.
Crowding percentile withheld — no market cap for ARBK 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 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 47,63247,632 | $136,704 | — | ADD 51% |
| 2 | Westside Investment Management, Inc. | 8,3508,350 | $23,965 | — | NEW |
| 3 | MORGAN STANLEY | 2,6882,688 | $7,715 | — | TRIM -33% |
| 4 | RHUMBLINE ADVISERS | 749749 | $2,149 | — | ADD 912% |
| 5 | UBS Group AG | 403403 | $1,157 | — | NEW |
| 6 | SBI Securities Co., Ltd. | 66 | $17 | — | ADD 50% |
| 7 | Farther Finance Advisors, LLC | 11 | $3 | — | — |
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 |
|---|---|---|---|---|---|---|---|
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | 59K | 48K | — | 113K | 32K | 48K | $136,704 |
| Westside Investment Management, Inc. | — | — | — | — | — | 8K | $23,965 |
| MORGAN STANLEY | 17K | 579 | 500 | 500 | 4K | 3K | $7,715 |
| RHUMBLINE ADVISERS | 4K | 168 | 168 | 8K | 74 | 749 | $2,149 |
| UBS Group AG | 147K | 33K | 50K | 6 | — | 403 | $1,157 |
| SBI Securities Co., Ltd. | 20K | 41K | 17K | 17K | 4 | 6 | $17 |
| Farther Finance Advisors, LLC | 400 | — | — | 271 | 1 | 1 | $3 |
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.
Holder count only — too few computable %-of-shares-outstanding quarters for a % pane. Line breaks are quarters with no 13F record, never interpolated.
| Quarter | Holders | Shares held | % shares out | Value held |
|---|---|---|---|---|
| 2026-Q1 | 7 |
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 | |
|---|---|---|---|
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | +16,068 | $46,115 | ADD |
| Westside Investment Management, Inc. | +8,350 | $23,965 | OPEN |
| RHUMBLINE ADVISERS | +675 | $1,937 | ADD |
| UBS Group AG | +403 | $1,157 | OPEN |
| SBI Securities Co., Ltd. | +2 | $6 | ADD |
| Biggest sellers | Δ shares | Δ value | |
|---|---|---|---|
| MORGAN STANLEY | −1,347 | $3,866 | TRIM |
| Signature Resources Capital Management, LLC | −9 | $26 | CLOSE |
| Arax Advisory Partners | −1 | $3 | CLOSE |
| JPMORGAN CHASE & CO | −1 | $3 | CLOSE |
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).
| 59,829 |
| — |
| $171,710 |
| 2025-Q4 | 8 | 35,689 | — | $121,699 |
| 2025-Q3 | 26 | 602,930 | — | $155,843 |
| 2025-Q2 | 23 | 4,916,384 | — | $915,913 |
| 2025-Q1 | 24 | 1,005,861 | — | $342,259 |
| 2024-Q4 | 28 | 1,498,776 | — | $843,412 |
| 2024-Q3 | 25 | 2,300,477 | — | $3M |
| 2024-Q2 | 28 | 2,348,180 | — | $3M |
| 2024-Q1 | 29 | 2,417,491 | — | $5M |
| 2023-Q4 | 30 | 1,419,425 | — | $5M |
| 2023-Q3 | 18 | 451,621 | — | $450,963 |
| 2023-Q2 | 15 | 603,920 | — | $962,481 |
| 2023-Q1 | 15 | 396,340 | — | $662,198 |
| 2022-Q4 | 24 | 300,665 | — | $322,746 |
| 2022-Q3 | 32 | 863,595 | — | $3M |
| 2022-Q2 | 29 | 884,205 | — | $3M |
| 2022-Q1 | 27 | 899,489 | — | $9M |
| 2021-Q4 | 31 | 760,644 | — | $9M |
| 2021-Q3 | 20 | 1,912,756 | — | $31M |
