Who owns Moleculin Biotech, Inc. (MBRX)
Which tracked institutional funds hold MBRX, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See MBRX company fundamentals →
Ownership as of the 2026-Q1 13F filings (latest filed 2026-05-15). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
Conviction spread
MBRX’s largest tracked holder by dollar value, ARMISTICE CAPITAL, LLC, sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in MBRX divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 20 tracked filers holding MBRX, 11 increased or opened the position and 6 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| SABBY MANAGEMENT, LLC new | 75,021 | $172K | 8.4% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 32,329 | $74K | 3.6% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 13,869 | $32K | 1.6% | 2026-Q1 |
| HRT FINANCIAL LP trimmed | 13,739 | $31K | 1.5% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 6,072 | $14K | 0.7% | 2026-Q1 |
| Rockefeller Capital Management L.P. added | 4,421 | $10K | 0.5% | 2026-Q1 |
| UBS Group AG trimmed | 3,409 | $8K | 0.4% | 2026-Q1 |
| Tower Research Capital LLC (TRC) added | 1,835 | $4K | 0.2% | 2026-Q1 |
| BlackRock, Inc. trimmed | 491 | $1K | 0.1% | 2026-Q1 |
| EFG International AG | 434 | $994 | 0.0% | 2026-Q1 |
| Pinnacle Wealth Planning Services, Inc. | 281 | $643 | 0.0% | 2026-Q1 |
| NFSG Corp | 114 | $261 | 0.0% | 2026-Q1 |
| SBI Securities Co., Ltd. added | 43 | $98 | 0.0% | 2026-Q1 |
| MORGAN STANLEY | 36 | $83 | 0.0% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 24 | $55 | 0.0% | 2026-Q1 |
| FMR LLC trimmed | 3 | $7 | 0.0% | 2026-Q1 |
| DANSKE BANK A/S | 2 | $5 | 0.0% | 2026-Q1 |
| Caitong International Asset Management Co., Ltd new | 2 | $5 | 0.0% | 2026-Q1 |
| CVA Family Office, LLC | 1 | $2 | 0.0% | 2026-Q1 |
| OSAIC HOLDINGS, INC. | 1 | $2 | 0.0% | 2026-Q1 |
| ARMISTICE CAPITAL, LLC added | 1,250,000 | $1M | 59.7% | 2025-Q1 stale |
| CITADEL ADVISORS LLC trimmed | 33,085 | $110K | 5.4% | 2025-Q4 stale |
| JANE STREET GROUP, LLC added | 22,550 | $75K | 3.7% | 2025-Q4 stale |
| Cetera Investment Advisers new | 70,000 | $68K | 3.3% | 2025-Q1 stale |
| VANGUARD GROUP INC trimmed | 15,544 | $51K | 2.5% | 2025-Q4 stale |
| LPL Financial LLC added | 58,080 | $31K | 1.5% | 2025-Q3 stale |
| CITIGROUP INC added | 85,283 | $26K | 1.3% | 2025-Q2 stale |
| XTX Topco Ltd added | 74,217 | $22K | 1.1% | 2025-Q2 stale |
| IEQ CAPITAL, LLC new | 36,363 | $19K | 0.9% | 2025-Q3 stale |
| Virtu Financial LLC added | 59,278 | $18K | 0.9% | 2025-Q2 stale |
| VERUS CAPITAL PARTNERS, LLC new | 43,000 | $13K | 0.6% | 2025-Q2 stale |
| Wealth Dimensions Group, Ltd. new | 20,000 | $11K | 0.5% | 2025-Q3 stale |
| Cambridge Investment Research Advisors, Inc. | 12,781 | $7K | 0.3% | 2025-Q3 stale |
| GOLDMAN SACHS GROUP INC added | 12,752 | $7K | 0.3% | 2025-Q3 stale |
| TRUIST FINANCIAL CORP | 10,500 | $6K | 0.3% | 2025-Q3 stale |
| Ethos Financial Group, LLC new | 10,034 | $5K | 0.3% | 2025-Q3 stale |
| Moors & Cabot, Inc. new | 10,000 | $5K | 0.3% | 2025-Q3 stale |
| Stone House Investment Management, LLC new | 3,300 | $996 | 0.0% | 2025-Q2 stale |
| BARCLAYS PLC trimmed | 344 | $335 | 0.0% | 2025-Q1 stale |
| Bogart Wealth, LLC | 300 | $159 | 0.0% | 2025-Q3 stale |
| BANK OF AMERICA CORP /DE/ trimmed | 36 | $119 | 0.0% | 2025-Q4 stale |
| Atlantic Union Bankshares Corp new | 379 | $115 | 0.0% | 2025-Q2 stale |
| Sandy Spring Bank | 89 | $87 | 0.0% | 2025-Q1 stale |
| North Star Investment Management Corp. | 17 | $9 | 0.0% | 2025-Q3 stale |
| NBC SECURITIES, INC. | 14 | $7 | 0.0% | 2025-Q3 stale |
| ROYAL BANK OF CANADA | 1 | — | 0.0% | 2025-Q3 stale |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | 0 | — | 0.0% | 2025-Q2 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.