Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in NEPH held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | WEXFORD CAPITAL LP | 3.6M | $10.7M | -0.5% | 33.165% | 1.77% |
| 2 | Topline Capital Management, LLC | 582K | $1.7M | -5.3% | 5.361% | 0.29% |
| 3 | VANGUARD CAPITAL MANAGEMENT LLC | 199K | $592K | — | 1.830% | 0.00% |
| 4 | Cornerstone Capital, Inc. | 129K | $384K | — | 1.185% | 0.04% |
| 5 | BARD ASSOCIATES INC | 121K | $361K | -0.3% | 1.116% | 0.09% |
| 6 | Mesirow Financial Investment Management, Inc. | 120K | $358K | +140.0% | 1.105% | 0.01% |
| 7 | MORGAN STANLEY | 111K | $331K | +517.6% | 1.022% | 0.00% |
| 8 | RENAISSANCE TECHNOLOGIES LLC | 99K | $296K | -4.2% | 0.916% | 0.00% |
| 9 | GEODE CAPITAL MANAGEMENT, LLC | 73K | $217K | -2.3% | 0.672% | 0.00% |
| 10 | HighTower Advisors, LLC | 60K | $178K | 0.0% | 0.550% | 0.00% |
| 11 | ESSEX INVESTMENT MANAGEMENT CO LLC | 39K | $116K | 0.0% | 0.359% | 0.02% |
| 12 | VANGUARD FIDUCIARY TRUST CO | 37K | $110K | — | 0.340% | 0.00% |
| 13 | BLAIR WILLIAM & CO/IL | 36K | $108K | 0.0% | 0.334% | 0.00% |
| 14 | De Lisle Partners LLP | 25K | $75K | 0.0% | 0.230% | 0.01% |
| 15 | CITADEL ADVISORS LLC | 21K | $62K | +0.9% | 0.192% | 0.00% |
| 16 | DIMENSIONAL FUND ADVISORS LP | 21K | $62K | +52.5% | 0.191% | 0.00% |
| 17 | NAVELLIER & ASSOCIATES INC | 19K | $57K | -29.6% | 0.176% | 0.01% |
| 18 | STATE STREET CORP | 16K | $47K | 0.0% | 0.145% | 0.00% |
| 19 | GOLDMAN SACHS GROUP INC | 14K | $42K | -25.4% | 0.131% | 0.00% |
| 20 | PRELUDE CAPITAL MANAGEMENT, LLC | 14K | $41K | -9.9% | 0.126% | 0.00% |
| 21 | ELKHORN PARTNERS LIMITED PARTNERSHIP | 12K | $36K | +71.4% | 0.111% | 0.02% |
| 22 | Spears Abacus Advisors LLC | 11K | $33K | 0.0% | 0.101% | 0.00% |
| 23 | NORTHERN TRUST CORP | 11K | $32K | 0.0% | 0.100% | 0.00% |
| 24 | ROYAL BANK OF CANADA | 747 | $2K | +1.2% | 0.007% | 0.00% |
| 25 | ADVISOR GROUP HOLDINGS, INC. | 175 | $521 | -89.2% | 0.002% | 0.00% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in NEPH — a direct measure of their conviction.
Filings activity in NEPH during Q1 2026, grouped by how each filer changed its position.
Institutions that opened a new NEPH position in Q1 2026
Institutions that fully closed their NEPH position in Q1 2026
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 27 | 23% | 44.13% | 26.30 pp | $16M | 37% |
| Q4 2025 | 35 | +46% | 70.43% | +5.01 pp | $26M | +7.7% |
| Q3 2025 | 24 | +14% | 65.42% | +10.69 pp | $24M | +20% |
| Q2 2025 | 21 | +11% | 54.73% | +32.75 pp | $20M | +149% |
| Q1 2025 | 19 | +0.0% | 21.98% | +3.10 pp | $8M | +16% |
| Q4 2024 | 19 | +5.6% | 18.88% | 1.17 pp | $7M | 5.8% |
| Q3 2024 | 18 | +0.0% | 20.05% | 4.92 pp | $7M | 20% |
| Q2 2024 | 18 | — | 24.97% | — | $9M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying NEPH stock.
Based on Q1 2026 13F filings, institutional ownership of Nephros, Inc. stands at 44.1%, held across 27 reporting institutions.
WEXFORD CAPITAL LP is the largest reported institutional holder of NEPH, with approximately 3,600,552 shares worth $0.01B as of Q1 2026.
Yes — 2 widely-followed marquee investors appear among the top 25 institutional holders of NEPH, including RENAISSANCE TECHNOLOGIES LLC, CITADEL ADVISORS LLC.
Our composite Smart Money Score for NEPH is 32 out of 100 (Bearish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
3 institutions opened new positions in NEPH during Q1 2026, while 11 fully exited. 3 added to existing positions and 21 trimmed.
NEPH institutional ownership fell by 26.30 percentage points quarter-over-quarter, with a net change of -8 holders.
The top 10 institutions account for 94.9% of all reported 13F value in NEPH, and the top 25 account for 100.0%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Nephros, Inc. (NEPH) Institutional Ownership