On paper, QuidelOrtho's institutional ownership exceeds 100% of its shares outstanding. The 94 funds that filed 13Fs in the May 2026 quarterly cycle collectively report 80.9 million shares held — against a 67.45 million share float. That implies the equivalent of ~120% of QDEL's float is being claimed by long holders.
This is not a data error. It is a structural feature of how 13F aggregation interacts with securities lending. The 13.5 million share gap between reported ownership and shares outstanding maps almost exactly onto the 12.8 million share short interest — a coincidence in number, but causal in mechanism. Below is the full picture as of the March 31, 2026 reporting date.
Key metrics
Why does institutional ownership exceed 100%?
Four mechanisms drive 13F aggregates above shares outstanding. Their explanatory power for QDEL specifically varies by an order of magnitude.
Securities lending double-counts shares.
When a long holder (Vanguard, say) lends shares to a short seller, the short seller sells them to a new buyer. On 13F filing day, both the original lender and the new buyer report the shares — the same economic share is counted twice. With 12.8M shares short, this mechanism alone accounts for essentially the entire over-reporting gap.
Beneficial vs. custodial overlap.
Custodians (State Street, BNY Mellon, Northern Trust) may report shares held in custody on Form 13F that the underlying investment manager also reports. Aggregators sometimes fail to fully de-duplicate these. For QDEL, this likely accounts for some residual but is not the primary driver.
Parent/subsidiary double reporting.
Vanguard has 4 entities filing separately; T. Rowe has 2. After analysis, maximum possible overlap is ~600K shares — the largest Vanguard entities (Portfolio Management, Capital Management) appear to be independent filers, not duplicates. This explains less than 5% of the gap.
Stale or overlapping 13F dates.
13Fs are filed up to 45 days after quarter-end. A "May 2026" snapshot blends filers reporting as of different dates. Holders who exited may still appear in the latest filed 13F. Material at the margin, but small relative to lending double-count.
Short interest is 12.8M shares. The unexplained ownership gap is 12.9M shares. The match is not a coincidence — it is the mechanism.
Securities lending economics
Long holders of heavily shorted small caps do not simply tolerate the borrow — they monetize it. With ~19% of QDEL's float on loan, the lending economics are material and explain why the largest holders (BlackRock, Fidelity, Vanguard, State Street) participate enthusiastically.
Who benefits the most
- Index funds (Vanguard, BlackRock/iShares, State Street, Geode) are the largest lenders — securities lending is a key revenue stream that offsets low expense ratios. For some ETFs, lending income exceeds the management fee.
- Custodial banks (BNY Mellon, State Street, Northern Trust) operate the lending programs and take a portion of the fee.
- Active managers may opt out to retain voting rights, but most participate.
- For QDEL specifically: top lenders are likely BlackRock (10.4M shares), Fidelity (6.6M), Vanguard entities (~7.6M combined), State Street (2.8M), Geode (1.7M).
Vanguard & T. Rowe — potential entity overlap
Sub-entities may already be rolled into the largest affiliated filer. Maximum overlap = sum of the smaller entities (the largest is assumed to be the parent/aggregate). This is an upper-bound estimate of double-count.
| Vanguard Portfolio Management LLC — independent filer | 4,031,768 |
| Vanguard Capital Management LLC — independent (not overlapping w/ above) | 3,052,710 |
| Vanguard Fiduciary Trust Co — possible overlap | 454,514 |
| Vanguard Asset Management Ltd — possible overlap | 62,479 |
| Vanguard — max possible overlap | 516,993 |
| T. Rowe Price Investment Management — largest, assumed parent | 5,629,965 |
| Price T. Rowe Associates Inc /MD/ — potential overlap | 82,922 |
| T. Rowe — max possible overlap | 82,922 |
| Combined max overlap (Vanguard + T. Rowe) | 599,915 (~0.9% of float) |
After removing the maximum-possible overlap, the unexplained gap is still 12.88M shares — within rounding of the 12.8M-share short interest. The conclusion is unambiguous: lending double-counting is the dominant driver. Entity duplication is a footnote.
Top 10 holders — May 2026
Figure 01 — Shares Held
Percentage figures shown to the right of each bar represent share of total float (67.45M). BlackRock alone holds ~15.5% of QDEL.
Full holdings table — all 94 filers
Every 13F filer reporting QDEL holdings as of the March 31, 2026 reference date. Sorted by shares held, with the percentage of float and the percentage of reported institutional ownership.
| # | Holder | Shares | % Float | % Inst. |
|---|---|---|---|---|
| 01 | BlackRock Inc. | 10,449,127 | 15.49% | 12.91% |
| 02 | FMR LLC | 6,591,152 | 9.77% | 8.14% |
| 03 | T. Rowe Price Investment Management Inc. | 5,629,965 | 8.35% | 6.96% |
| 04 | Newtyn Management, LLC | 4,558,472 | 6.76% | 5.63% |
| 05 | Vanguard Portfolio Management LLC | 4,031,768 | 5.98% | 4.98% |
| 06 | Rubric Capital Management LP | 3,306,281 | 4.90% | 4.09% |
| 07 | Invesco LTD | 3,117,469 | 4.62% | 3.85% |
| 08 | Vanguard Capital Management LLC | 3,052,710 | 4.53% | 3.77% |
| 09 | Dimensional Fund Advisors INC | 3,048,768 | 4.52% | 3.77% |
| 10 | American Century Companies INC | 2,856,132 | 4.23% | 3.53% |
| 11 | State Street CORP | 2,786,621 | 4.13% | 3.44% |
| 12 | Goldman Sachs Group Inc/ | 2,412,411 | 3.58% | 2.98% |
| 13 | Frontier Capital Management Co LLC | 1,752,613 | 2.60% | 2.17% |
| 14 | Geode Capital Management LLC | 1,715,199 | 2.54% | 2.12% |
| 15 | Segall Bryant & Hamill | 1,543,410 | 2.29% | 1.91% |
| 16 | Neuberger Berman Group LLC | 1,530,414 | 2.27% | 1.89% |
| 17 | Paradigm Capital Management Inc/Ny | 1,525,900 | 2.26% | 1.89% |
| 18 | Private Management Group INC | 1,384,769 | 2.05% | 1.71% |
| 19 | Rice Hall James & Associates LLC | 1,026,420 | 1.52% | 1.27% |
| 20 | Morgan Stanley | 1,023,510 | 1.52% | 1.26% |
| 21 | Allianz Asset Management AG | 1,006,337 | 1.49% | 1.24% |
| 22 | Silvercrest Asset Management Group LLC | 892,407 | 1.32% | 1.10% |
| 23 | Schwab Charles Investment Management INC | 830,059 | 1.23% | 1.03% |
| 24 | Point72 Asset Management L.P. | 762,169 | 1.13% | 0.94% |
| 25 | Northern Trust CORP | 689,794 | 1.02% | 0.85% |
| 26 | UBS Group AG | 542,002 | 0.80% | 0.67% |
| 27 | Vanguard Fiduciary Trust Co NEW | 454,514 | 0.67% | 0.56% |
| 28 | Goodman Financial CORP | 437,157 | 0.65% | 0.54% |
| 29 | Bank Of New York Mellon CORP | 427,645 | 0.63% | 0.53% |
| 30 | Aristotle Capital Boston LLC | 420,402 | 0.62% | 0.52% |
| 31 | Thompson Siegel & Walmsley LLC | 410,234 | 0.61% | 0.51% |
| 32 | Bridgeway Capital Management INC | 409,427 | 0.61% | 0.51% |
| 33 | Gagnon Securities LLC | 403,325 | 0.60% | 0.50% |
| 34 | Sio Capital Management, LLC NEW | 359,011 | 0.53% | 0.44% |
| 35 | Skylands Capital LLC | 341,554 | 0.51% | 0.42% |
| 36 | Principal Financial Group INC | 331,184 | 0.49% | 0.41% |
| 37 | Lightrock Netherlands B.V. | 314,547 | 0.47% | 0.39% |
| 38 | Gem Investment Advisors LLC | 296,665 | 0.44% | 0.37% |
| 39 | Bayberry Capital Partners LP | 282,600 | 0.42% | 0.35% |
| 40 | Millennium Management LLC | 282,217 | 0.42% | 0.35% |
| 41 | D E Shaw & Co INC | 274,699 | 0.41% | 0.34% |
| 42 | SEI Investments Co | 269,178 | 0.40% | 0.33% |
| 43 | TD Asset Management INC | 261,268 | 0.39% | 0.32% |
| 44 | Ameriprise Financial INC | 254,497 | 0.38% | 0.31% |
| 45 | Empowered Funds LLC | 254,217 | 0.38% | 0.31% |
| 46 | Gamco Investors INC ET AL | 253,900 | 0.38% | 0.31% |
| 47 | Stanley Capital Management LLC | 252,000 | 0.37% | 0.31% |
| 48 | Public Sector Pension Investment Board | 243,017 | 0.36% | 0.30% |
| 49 | Monaco Asset Management SAM | 242,595 | 0.36% | 0.30% |
| 50 | Tudor Investment CORP ET AL NEW | 234,509 | 0.35% | 0.29% |
| 51 | Systematic Financial Management LP | 225,853 | 0.33% | 0.28% |
| 52 | Nuveen LLC | 224,156 | 0.33% | 0.28% |
| 53 | Tejara Capital Ltd | 216,090 | 0.32% | 0.27% |
| 54 | Susquehanna Portfolio Strategies LLC | 213,637 | 0.32% | 0.26% |
| 55 | UBS Global Asset Management Americas INC | 196,961 | 0.29% | 0.24% |
| 56 | SaddleRock Capital Management LLC | 196,141 | 0.29% | 0.24% |
| 57 | Leeward Investments LLC - MA | 186,851 | 0.28% | 0.23% |
| 58 | AQR Capital Management LLC | 174,720 | 0.26% | 0.22% |
| 59 | Rhumbline Advisers | 170,816 | 0.25% | 0.21% |
| 60 | Gabelli Funds LLC | 166,400 | 0.25% | 0.21% |
| 61 | Legal & General Group PLC | 163,484 | 0.24% | 0.20% |
| 62 | XTX Topco Ltd NEW | 161,643 | 0.24% | 0.20% |
| 63 | Beaconlight Capital, LLC | 152,057 | 0.23% | 0.19% |
| 64 | Quantinno Capital Management LP | 150,646 | 0.22% | 0.19% |
| 65 | Ballast Asset Management LP | 145,960 | 0.22% | 0.18% |
| 66 | J P Morgan Chase & Co | 136,736 | 0.20% | 0.17% |
| 67 | Swiss National Bank | 133,940 | 0.20% | 0.17% |
| 68 | Phocas Financial CORP | 132,882 | 0.20% | 0.16% |
| 69 | Marshall Wace LLP NEW | 131,833 | 0.20% | 0.16% |
| 70 | Bank Of America CORP /DE/ | 126,973 | 0.19% | 0.16% |
| 71 | Edgestream Partners L.P. NEW | 117,888 | 0.17% | 0.15% |
| 72 | Deutsche Bank AG | 113,387 | 0.17% | 0.14% |
| 73 | Parkman Healthcare Partners LLC | 101,764 | 0.15% | 0.13% |
| 74 | Trexquant Investment LP NEW | 97,019 | 0.14% | 0.12% |
| 75 | Federated Investors INC /PA/ NEW | 94,193 | 0.14% | 0.12% |
| 76 | California State Teachers Retirement System | 92,989 | 0.14% | 0.11% |
| 77 | Price T Rowe Associates INC /MD/ | 82,922 | 0.12% | 0.10% |
| 78 | Birchview Capital LP | 82,548 | 0.12% | 0.10% |
| 79 | Summit Trail Advisors LLC | 82,484 | 0.12% | 0.10% |
| 80 | Alliancebernstein L.P. | 80,843 | 0.12% | 0.10% |
| 81 | Raymond James Financial INC | 76,719 | 0.11% | 0.09% |
| 82 | Invenomic Capital Management LP NEW | 76,267 | 0.11% | 0.09% |
| 83 | Prudential Financial INC | 70,531 | 0.10% | 0.09% |
| 84 | Moody National Bank Trust Division | 69,959 | 0.10% | 0.09% |
| 85 | VANGUARD ASSET MANAGEMENT Ltd | 62,479 | 0.09% | 0.08% |
| 86 | Wedge Capital Management L L P/Nc | 56,182 | 0.08% | 0.07% |
| 87 | New York State Teachers Retirement System | 54,594 | 0.08% | 0.07% |
| 88 | Fifth Third Bancorp | 54,328 | 0.08% | 0.07% |
| 89 | Clearline Capital LP | 49,885 | 0.07% | 0.06% |
| 90 | Y-Intercept (Hong Kong) Ltd NEW | 48,087 | 0.07% | 0.06% |
| 91 | New York State Common Retirement Fund | 45,705 | 0.07% | 0.06% |
| 92 | Thrivent Financial For Lutherans | 45,343 | 0.07% | 0.06% |
| 93 | Illinois Municipal Retirement Fund | 43,751 | 0.06% | 0.05% |
| 94 | State Of Wisconsin Investment Board | 43,598 | 0.06% | 0.05% |
The conclusion in one line
QDEL's 120% reported institutional ownership is securities-lending double-counting in plain sight. The cap table is concentrated — BlackRock, Fidelity, T. Rowe, Newtyn, and the two largest Vanguard entities together hold the equivalent of 50%+ of float — and roughly a fifth of that ownership is simultaneously on loan to short sellers, generating ~$5M in annual lending income for long holders to offset the position. Anyone tracking this name needs to read 13F totals through that lens.
- Shares outstanding: QuidelOrtho 10-Q FY2026 (SEC EDGAR), filing date Mar 29, 2026
- 13F holdings: aggregated from individual Q1 2026 13F filings (SEC EDGAR), reference date Mar 31, 2026
- Short interest: MarketWatch aggregator — 12.8M shares, ~19% of float
- Securities lending economics: industry-standard rate ranges (2–15% for heavily shorted small caps), broker split convention (60–80% to lender)
This report is for informational purposes only and does not constitute investment advice. Holdings data is as of the most recent 13F reporting date and may not reflect current positions. Securities lending figures are illustrative based on disclosed short interest and industry-standard rates.