Alpha Pro Tech Ltd (NYSE: APT), an SEC filer in Orthopedic, Prosthetic & Surgical Appliances & Supplies, closed at $5.35, -2.2%, on 2026-08-28, with a market cap of $56M as of 2026-08-27, a trailing P/E of 16.6, a return on equity of 5.7%, a net margin of 6.0% and 3-year sales growth of -1.6%. Institutional ownership, earnings history and filed financials are on the tabs below.
| # | Holder | Shares | Value | % of shares out | Δ QoQ |
|---|---|---|---|---|---|
| 1 | NEEDHAM INVESTMENT MANAGEMENT LLC | 642,500642,500 | $3M | 6.31% | — |
| 2 | VANGUARD CAPITAL MANAGEMENT LLC | 553,674553,674 | $2M | 5.44% | NEW† |
| 3 | RENAISSANCE TECHNOLOGIES LLC | 544,072544,072 | $2M | 5.34% | ADD 4% |
| 4 | BlackRock, Inc. | 271,800271,800 | $1M | 2.67% | — |
| 5 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 141,226141,226 | $627,043 | 1.39% | ADD 107% |
| 6 | DIMENSIONAL FUND ADVISORS LP | 137,335137,335 | $609,767 | 1.35% | — |
| 7 | ACADIAN ASSET MANAGEMENT LLC | 133,352133,352 | $591,000 | 1.31% | — |
| 8 | GROUP ONE TRADING LLC | 113,071113,071 | $502,035 | 1.11% | NEW |
| 9 | BRIDGEWAY CAPITAL MANAGEMENT, LLC | 78,52578,525 | $348,651 | 0.77% | — |
| 10 | GEODE CAPITAL MANAGEMENT, LLC | 68,38668,386 | $304,142 | 0.67% | TRIM -26% |
† NEW this big is usually a rename.
Ranked by each filer’s own reported value, not shares.
| Biggest buyers | Δ shares | Δ value | |
|---|---|---|---|
| VANGUARD CAPITAL MANAGEMENT LLC | +553,674 | $2M | OPEN |
| GROUP ONE TRADING LLC | +113,071 | $502,035 | OPEN |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | +72,915 | $323,743 | ADD |
| VANGUARD FIDUCIARY TRUST CO | +51,432 | $228,358 | OPEN |
| JANE STREET GROUP, LLC | +25,630 | $113,797 | OPEN |
| Biggest sellers | Δ shares | Δ value | |
|---|---|---|---|
| VANGUARD GROUP INC | −609,067 | $3M | CLOSE |
| GEODE CAPITAL MANAGEMENT, LLC | −24,486 | $108,718 | TRIM |
| CITADEL ADVISORS LLC | −21,351 | $94,798 | CLOSE |
| OSAIC HOLDINGS, INC. | −18,700 | $83,028 | TRIM |
| NewEdge Advisors, LLC | −14,123 | $62,706 | TRIM |
Prior quarter split-rebased · 13Fs are long, US-listed only.
| Holder | 2024-Q4 | 2025-Q1 | 2025-Q2 | 2025-Q3 | 2025-Q4 | 2026-Q1 | Latest value |
|---|---|---|---|---|---|---|---|
| NEEDHAM INVESTMENT MANAGEMENT LLC | 613K | 613K | 613K | 635K | 643K | 643K | $3M |
| VANGUARD CAPITAL MANAGEMENT LLC | — | — | — | — | — | 554K | $2M |
| RENAISSANCE TECHNOLOGIES LLC | 565K | 540K | 536K | 536K | 523K | 544K | $2M |
| BlackRock, Inc. | 273K | 273K | 271K | 272K | 270K | 272K | $1M |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | — | 21K | 84K | 64K | 68K | 141K | $627,043 |
| DIMENSIONAL FUND ADVISORS LP | 141K | 144K | 148K | 148K | 137K | 137K | $609,767 |
| ACADIAN ASSET MANAGEMENT LLC | 154K | 149K | 147K | 144K | 133K | 133K | $591,000 |
| GROUP ONE TRADING LLC | — | 5K | 16K | 14K | — | 113K | $502,035 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 77K | 77K | 77K | 79K | 79K | 79K | $348,651 |
| GEODE CAPITAL MANAGEMENT, LLC | 97K | 97K | 98K | 99K | 93K | 68K | $304,142 |
Green = added, red = trimmed, grey = held; a dash is a quarter with no 13F on file — a gap, not an exit.
Breaks = no 13F that quarter.
Short interest has its own tab now — open SI →
SEC Form 13F · ~10,250 filers, 10y · long-only, US-listed, filed ≤45d after quarter-end.
