Aureus Asset Management, LLC is an SEC-registered investment adviser based in Boston, MA that reports managing 4 hedge funds on Form ADV. It reports $8.4 billion in regulatory assets under management. Its private funds, of all types, hold $182.6 million in gross assets. Its disclosed U.S. stock holdings returned an estimated +5.0% 2026 YTD through Jun 30 (S&P 500: +9.5%), based on 13F filings. Over a longer period they returned an estimated +26.5% from Q3 2024 to Q2 2026, compared with +37.2% for the S&P 500, based on 13F filings.
- Regulatory assets under management
- $8.4 billionForm ADV Item 5.F
- Gross assets of private funds
- $182.6 millionAll private fund types, Form ADV
- Hedge funds managed
- 44 private funds in total
- Employees
- 14Form ADV Item 5.A
- Registration
- SEC-registered adviserCRD 136674
- Latest Form ADV
- 10/28/2026Disciplinary disclosures: none reported
Estimated 13F portfolio performance
Estimated by AltMountain, derived from the firm’s public Form 13F filings. Not reported by the firm and not the return of any fund.
| Quarter | Est. 13F return | S&P 500 |
|---|---|---|
| Q2 2026 | +13.5% | +14.8% |
| Q1 2026 | -7.5% | -4.6% |
| Q4 2025 | +2.1% | +2.4% |
| Q3 2025 | +3.5% | +7.8% |
| Q2 2025 | +8.9% | +10.4% |
| Q1 2025 | -4.6% | -4.5% |
| Q4 2024 | +2.8% | +2.1% |
| Q3 2024 | +6.8% | +5.4% |
Estimate of the firm's disclosed long U.S. stock portfolio from its quarterly 13F filings, holding each quarter-end portfolio to the next quarter-end at prices implied by all 13F filers. It is a price return before dividends and fees, ignores shorts, options, bonds, cash and trading within the quarter, and is not the return of any fund. Disclosures
Manager of this firm? Report your fund’s actual net return, or email hello@altmountain.com to correct or remove this estimate. Removal requests from the firm are honored.
13F holdings as of Sep 30, 2026
The 50 largest of 222 share positions ($1,672,153,904) reported by Aureus Asset Management, LLC on Form 13F for the quarter ended Sep 30, 2026, filed Nov 13, 2026. Shown as filed with the SEC. Original filing on SEC.gov ↗ The estimated return above runs through Jun 30, 2026; it is updated when the SEC publishes its complete data for the quarter.
| Stock | Value | % of 13F portfolio | Shares | Shares vs prior quarter |
|---|---|---|---|---|
| Microsoft Corp | $90,526,639 | 5.41% | 176,500 | -1.55% |
| Alphabet Inc | $83,632,543 | 5.00% | 243,061 | -3.08% |
| Apple Inc | $79,109,787 | 4.73% | 237,553 | -1.73% |
| Amazon Com Inc | $70,152,800 | 4.20% | 281,569 | -0.20% |
| Visa Inc | $61,022,158 | 3.65% | 169,822 | -1.61% |
| Nvidia Corporation | $58,328,987 | 3.49% | 255,403 | -0.30% |
| Schwab Charles Corp | $56,860,557 | 3.40% | 581,753 | -3.13% |
| Meta Platforms Inc | $54,444,034 | 3.26% | 75,077 | -2.10% |
| Broadcom Inc | $54,067,540 | 3.23% | 153,955 | -1.34% |
| Applied Matls Inc | $51,922,634 | 3.11% | 101,534 | -2.75% |
| Waste Connections Inc | $50,328,004 | 3.01% | 326,954 | +0.25% |
| Taiwan Semiconductor Manufac | $50,321,365 | 3.01% | 110,308 | -1.05% |
| Linde PLC | $49,650,039 | 2.97% | 104,603 | -1.06% |
| Thermo Fisher Scientific Inc | $49,590,147 | 2.97% | 73,461 | -1.80% |
| Unitedhealth Group Inc | $46,481,285 | 2.78% | 126,624 | -0.94% |
| Nextera Energy Inc | $45,232,435 | 2.71% | 597,207 | +0.24% |
| S&P Global Inc | $34,444,356 | 2.06% | 87,318 | +2.69% |
| Abbott Laboratories | $33,943,870 | 2.03% | 343,457 | +9.43% |
| American Express Co | $33,371,427 | 2.00% | 109,738 | -0.94% |
| Apollo Global Mgmt Inc | $32,614,968 | 1.95% | 281,018 | -1.64% |
| Texas Instrs Inc | $31,127,794 | 1.86% | 111,135 | +52.92% |
| Wabtec | $28,698,198 | 1.72% | 99,931 | -3.81% |
| Oracle Corp | $28,370,624 | 1.70% | 206,632 | +41.32% |
| Blackstone Inc | $27,040,957 | 1.62% | 241,243 | +1.24% |
| Idex Corp | $25,469,698 | 1.52% | 111,719 | +23.82% |
| CNX Res Corp | $21,999,412 | 1.32% | 705,788 | -0.90% |
| American WTR WKS Co Inc New | $20,163,684 | 1.21% | 155,740 | -5.07% |
| Ishares TR | $18,851,451 | 1.13% | 24,615 | +2.50% |
| Vertex Pharmaceuticals Inc | $17,250,116 | 1.03% | 32,995 | +648.53% |
| Moog Inc | $16,465,337 | 0.98% | 43,163 | -1.23% |
| Alphabet Inc | $15,419,081 | 0.92% | 45,252 | -4.51% |
| Flowserve Corp | $14,609,230 | 0.87% | 199,798 | -1.49% |
| Morgan Stanley | $9,807,507 | 0.59% | 52,145 | +2.66% |
| Williams Cos Inc | $9,509,987 | 0.57% | 139,914 | -0.55% |
| Agilent Technologies Inc | $9,315,290 | 0.56% | 54,061 | +0.11% |
| Service Corp Intl | $8,902,733 | 0.53% | 116,910 | -0.46% |
| Steris PLC | $8,853,140 | 0.53% | 42,156 | -0.22% |
| Wesco Intl Inc | $8,802,531 | 0.53% | 24,479 | -0.71% |
| Coca Cola Co | $7,922,373 | 0.47% | 92,035 | -0.50% |
| Jpmorgan Chase & Co | $7,011,641 | 0.42% | 21,194 | Unchanged |
| State STR SPDR S&P 500 ETF T | $6,539,552 | 0.39% | 8,575 | -0.13% |
| Ishares TR | $5,944,145 | 0.36% | 21,390 | +0.40% |
| Dell Technologies Inc | $5,856,393 | 0.35% | 10,887 | +4.79% |
| Cme Group Inc | $5,679,727 | 0.34% | 21,680 | +0.32% |
| Cabot Corp | $5,159,123 | 0.31% | 67,080 | Unchanged |
| Ishares TR | $5,061,243 | 0.30% | 20,414 | -20.92% |
| Micron Technology Inc | $4,967,673 | 0.30% | 4,664 | Unchanged |
| Gaming & Leisure P | $4,963,576 | 0.30% | 130,724 | -10.02% |
| Qxo Inc | $4,782,999 | 0.29% | 409,153 | -0.27% |
| Spotify Technology S A | $4,768,526 | 0.29% | 9,784 | +73.48% |
Changes since Jun 30, 2026
Comparing the share counts in the two quarter-end filings: 9 new positions, 26 sold out, 65 increased, 85 reduced and 63 unchanged.
New positions
| Stock | Value | Shares |
|---|---|---|
| Hut 8 Corp | $946,583 | 10,994 |
| SK Hynix Inc Fsponsored ADR 1 ADR Reps 0.1 ORD SHS | $772,141 | 4,193 |
| Exxonmobil Holdings Corp Com SHS | $635,765 | 3,906 |
| Henry Jack & Assoc Inc | $282,899 | 1,975 |
| Zebra Technologies Corporati | $255,344 | 684 |
| Integer Hldgs Corp | $234,000 | 1,852 |
| Resmed Inc | $225,964 | 1,022 |
| Cadence Design System Inc | $224,526 | 680 |
| Abrdn ETFS | $219,087 | 5,695 |
Sold out
| Stock | Value at Jun 30, 2026 | Shares held then |
|---|---|---|
| Honeywell Aerospace Inc | $2,467,142 | 11,159 |
| Ishares TR | $1,109,700 | 6,000 |
| Trane Technologies PLC | $584,972 | 1,191 |
| Exxon Mobil Corp | $510,839 | 3,736 |
| Nice LTD | $436,716 | 4,807 |
| Idexx Labs Inc | $401,147 | 762 |
| Tko Group Holdings Inc | $394,769 | 1,961 |
| Xylem Inc | $366,451 | 3,100 |
| Rxo Inc | $275,900 | 10,000 |
| Walmart Inc | $254,608 | 2,248 |
| Saia Inc | $237,534 | 564 |
| Lennox Intl Inc | $230,326 | 402 |
| Vulcan Matls Co | $229,518 | 778 |
| Digital Rlty TR Inc | $226,271 | 1,260 |
| Watsco Inc | $223,784 | 537 |
| International Business Machs | $218,781 | 778 |
| Servicetitan Inc | $210,787 | 2,981 |
| Parsons Corp Del | $209,560 | 4,000 |
| Astrazeneca PLC | $209,530 | 1,105 |
| Qualcomm Inc | $207,889 | 1,125 |
Largest increases
| Stock | Change in shares | Change | Value now | Shares now |
|---|---|---|---|---|
| Vertex Pharmaceuticals Inc | +28,587 | +648.53% | $17,250,116 | 32,995 |
| Texas Instrs Inc | +38,460 | +52.92% | $31,127,794 | 111,135 |
| Oracle Corp | +60,412 | +41.32% | $28,370,624 | 206,632 |
| Idex Corp | +21,495 | +23.82% | $25,469,698 | 111,719 |
| Abbott Laboratories | +29,586 | +9.43% | $33,943,870 | 343,457 |
| Spotify Technology S A | +4,144 | +73.48% | $4,768,526 | 9,784 |
| SLB Limited | +30,792 | +96.76% | $3,050,661 | 62,616 |
| Ishares Gold TR | +17,933 | +210.21% | $2,066,826 | 26,464 |
| Opus Genetics Inc | +207,529 | +356.58% | $1,286,128 | 265,729 |
| S&P Global Inc | +2,286 | +2.69% | $34,444,356 | 87,318 |
| Ollies Bargain Outlet Hldgs | +10,342 | +101.07% | $1,762,249 | 20,575 |
| NXP Semiconductors N V | +1,943 | +23.55% | $2,420,906 | 10,192 |
| Ishares TR | +600 | +2.50% | $18,851,451 | 24,615 |
| Airbnb Inc | +2,769 | +53.61% | $1,274,597 | 7,934 |
| Alibaba Group Hldg LTD | +4,035 | +30.22% | $1,869,798 | 17,387 |
| Blackrock ETF Trust II | +7,510 | +10.02% | $4,277,428 | 82,445 |
| Invesco Exchange Traded FD T | +1,709 | +11.74% | $3,382,852 | 16,262 |
| Blackstone Inc | +2,944 | +1.24% | $27,040,957 | 241,243 |
| Lazard Inc | +8,899 | +23.16% | $1,714,331 | 47,318 |
| Ishares TR | +3,709 | +59.47% | $752,117 | 9,946 |
Largest reductions
| Stock | Change in shares | Change | Value now | Shares now |
|---|---|---|---|---|
| Alphabet Inc | -7,736 | -3.08% | $83,632,543 | 243,061 |
| American Tower Corp | -14,179 | -91.34% | $219,999 | 1,344 |
| Schwab Charles Corp | -18,801 | -3.13% | $56,860,557 | 581,753 |
| Applied Matls Inc | -2,869 | -2.75% | $51,922,634 | 101,534 |
| Microsoft Corp | -2,778 | -1.55% | $90,526,639 | 176,500 |
| Booking Holdings Inc | -8,675 | -84.84% | $252,511 | 1,550 |
| Apple Inc | -4,184 | -1.73% | $79,109,787 | 237,553 |
| Ishares TR | -5,400 | -20.92% | $5,061,243 | 20,414 |
| Meta Platforms Inc | -1,613 | -2.10% | $54,444,034 | 75,077 |
| Wabtec | -3,962 | -3.81% | $28,698,198 | 99,931 |
| Boeing Co | -6,004 | -77.93% | $316,285 | 1,700 |
| American WTR WKS Co Inc New | -8,323 | -5.07% | $20,163,684 | 155,740 |
| Visa Inc | -2,775 | -1.61% | $61,022,158 | 169,822 |
| Thermo Fisher Scientific Inc | -1,344 | -1.80% | $49,590,147 | 73,461 |
| Palo Alto Networks Inc | -2,067 | -23.80% | $2,629,000 | 6,617 |
| Berkshire Hathaway Inc Del | -1 | -20.00% | $2,988,020 | 4 |
| Broadcom Inc | -2,094 | -1.34% | $54,067,540 | 153,955 |
| Alphabet Inc | -2,137 | -4.51% | $15,419,081 | 45,252 |
| Okta Inc | -3,190 | -20.70% | $2,555,533 | 12,221 |
| Gaming & Leisure P | -14,561 | -10.02% | $4,963,576 | 130,724 |
Each list shows up to 20 positions, largest first by dollar amount. Changes compare two quarter-end snapshots, with the earlier share count adjusted for stock splits AltMountain detected. They do not show when, or at what price, anything was bought or sold.
From public Form 13F filings, not verified. Form 13F is filed up to 45 days after the quarter ends, so positions may have changed. It lists only certain long positions in U.S.-listed stocks and exchange-traded funds; options are not shown here, and short positions, most bonds, cash, non-U.S. securities and private investments are not reported at all, so a holding may be one side of a hedge. A filing covers the manager as a whole, not any single fund, and filings contain errors. This is not investment advice or a recommendation to buy or sell any security. Disclosures
Private funds reported on Form ADV (3)
As reported in the adviser's Form ADV filed Mar 28, 2024. Funds also listed from Form D are shown above.
From SEC filings. Firm data comes from the SEC's Form ADV data as of Oct 2, 2026; performance estimates come from Form 13F. AltMountain has not verified this information, and it is not an offer, solicitation or recommendation. Full disclosures