Who owns Aeluma (ALMU)?
Aeluma's largest shareholders, according to SEC filings, are Mark N. Tompkins (10.1%, Former 10% Owner), Jonathan Klamkin (7.2%, Chief Executive Officer) and BlackRock (5.5%). In all, 61 holders named in SEC filings declare between 47.1% and 50.4% of its shares, and 41 smaller fund managers another 0.47%.
Aeluma's largest shareholders
| Holder | Filing | Shares | Share of capital | As of | Holding since (13F) |
|---|---|---|---|---|---|
| Mark N. Tompkins | Form 4 | 1.8M | 10.1% | Feb 4, 2026 | — |
| Jonathan Klamkin | Form 4 | 1.3M | 7.2% | Sep 21, 2026 | — |
| BlackRock | 13F | 973,235 | 5.5% | Jun 30, 2026 | Q2 2025 |
| D. E. Shaw | 13F | 797,983 | 4.5% | Jun 30, 2026 | Q1 2026 |
| Vanguard | 13F | 770,992 | 4.4% | Jun 30, 2026 | Q2 2025 |
| Millennium | 13F | 529,005 | 3.0% | Jun 30, 2026 | Q3 2025 |
| Steven Denbaars | Form 4 | 345,209 | 2.0% | Aug 27, 2026 | — |
| Geode Capital | 13F | 318,018 | 1.8% | Jun 30, 2026 | Q2 2025 |
| State Street | 13F | 254,168 | 1.4% | Jun 30, 2026 | Q2 2025 |
| Apis Capital Advisors, LLC | 13F | 194,000 | 1.1% | Jun 30, 2026 | Q1 2025 |
| AWM Investment Company, Inc. | 13F | 131,404 | 0.74% | Jun 30, 2026 | Q3 2025 |
| Northern Trust | 13F | 123,505 | 0.70% | Jun 30, 2026 | Q2 2025 |
| Marshall Wace | 13F | 95,964 | 0.54% | Jun 30, 2026 | Q1 2026 |
| BNY | 13F | 92,697 | 0.52% | Jun 30, 2026 | Q2 2025 |
| LAZARD ASSET MANAGEMENT LLC | 13F | 90,586 | 0.51% | Jun 30, 2026 | Q2 2026 |
| Christopher P. Stewart | Form 4 | 67,781 | 0.38% | Sep 30, 2026 | — |
| Westside Investment Management, Inc. | 13F | 52,575 | 0.30% | Jun 30, 2026 | Q3 2025 |
| WEDBUSH SECURITIES INC | 13F | 51,425 | 0.29% | Jun 30, 2026 | Q2 2026 |
| UBS | 13F | 47,078 | 0.27% | Jun 30, 2026 | Q1 2025 |
| Citadel | 13F | 41,219 | 0.23% | Jun 30, 2026 | Q2 2026 |
| Morgan Stanley | 13F | 41,155 | 0.23% | Jun 30, 2026 | Q2 2025 |
| LPL Financial LLC | 13F | 38,878 | 0.22% | Jun 30, 2026 | Q3 2025 |
| Goldman Sachs | 13F | 38,571 | 0.22% | Jun 30, 2026 | Q4 2025 |
| Michael Byron | Form 4 | 38,343 | 0.22% | Sep 21, 2026 | — |
| Fortitude Advisory Group L.L.C. | 13F | 37,567 | 0.21% | Jun 30, 2026 | Q1 2026 |
Aeluma ownership breakdown
61 holders named in SEC filings declare between 47.1% and 50.4% of Aeluma's shares outstanding, as of Sep 30, 2026. The largest are Mark N. Tompkins (10.1%), Jonathan Klamkin (7.2%) and BlackRock (5.5%); the five largest hold 31.7% together. Another 41 institutions hold small positions worth 0.47%. At least 49.1% of the shares appear in no ownership filing: investors who do not have to report, mostly individuals. From Mar 31, 2026 to Jun 30, 2026, institutions that filed both quarters bought 8.8% and sold 5.7% of the shares, a net purchase of 3.1%; 19 opened a position, 29 added, 27 reduced and 11 sold out. Biggest buyers: D. E. Shaw (+772,983 shares) and Millennium (+130,706 shares). Biggest sellers: RAYMOND JAMES FINANCIAL INC (-267,572) and Polar Asset Management Partners Inc. (-91,030). Directors and officers, from their latest Form 4: Mark N. Tompkins (10.1%), Jonathan Klamkin (7.2%) and Steven Denbaars (2.0%). Over time, 90 managers declared Aeluma in their 13F for Q2 2026, against 8 for Q1 2025: together at most 29.0% of the shares outstanding, against 7.3%.
Aeluma institutional ownership over time
| Quarter | 13F managers | Share of the company (upper bound) | Value declared | Held by stock pickers |
|---|---|---|---|---|
| Q4 2025 | 74 | 22.4% | $68.6M | 31.1% |
| Q2 2026 | 90 | 29.0% | $113.2M | 51.0% |
From SEC Form 13F, every quarter since the end of 2019, read like the current quarter: entities of a house summed, a value contradicting its share count set aside. The share of the company is an upper bound — two managers can declare the same shares — over the shares outstanding at that date.
Questions about Aeluma's shareholders
Who is the largest shareholder of Aeluma?
Mark N. Tompkins, with 10.1% of Aeluma's shares (1.8 million shares), according to the latest Form 4, dated Feb 4, 2026.
What is Aeluma's institutional ownership?
In their 13F filings for Q2 2026, 90 fund managers declared Aeluma shares: at most 29.0% of the shares outstanding — an upper bound, since two managers can report the same shares. With large shareholders (Schedule 13D/G) and directors and officers (Form 4), 61 named holders declare between 47.1% and 50.4% of the shares.
How much of Aeluma does BlackRock own?
BlackRock declared 973,235 shares, 5.5% of Aeluma's shares, in its 13F filing for the quarter ended Jun 30, 2026, up 0.64 percentage points from its previous filing (Mar 31, 2026).
How much of Aeluma does D. E. Shaw own?
D. E. Shaw declared 797,983 shares, 4.5% of Aeluma's shares, in its 13F filing for the quarter ended Jun 30, 2026, up 4.38 percentage points from its previous filing (Mar 31, 2026).
How much Aeluma stock does Mark N. Tompkins own?
Mark N. Tompkins, Former 10% Owner, declared 1.8 million shares, 10.1% of Aeluma's shares, in the latest Form 4, dated Feb 4, 2026.
Who bought and sold Aeluma stock last quarter?
From Mar 31, 2026 to Jun 30, 2026, fund managers that filed both quarters bought 8.8% of Aeluma's shares and sold 5.7%: 19 opened a position and 11 sold out. Biggest buyers: D. E. Shaw (+772,983 shares), Millennium (+130,706 shares) and BlackRock (+113,528 shares). Biggest sellers: RAYMOND JAMES FINANCIAL INC (−267,572 shares), Polar Asset Management Partners Inc. (−91,030 shares) and UBS (−73,932 shares).
How much of Aeluma do individual investors own?
No filing says it directly: individual investors do not have to report their holdings. At least 49.1% of Aeluma's shares appear in no ownership filing — retail investors, holders below the reporting thresholds and foreign funds.
Who owns the other AI companies? The largest shareholder of each, from SEC filings.