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Aureus Asset Management, LLC — 13F Holdings & Portfolio

CIK 1381296 · latest 13F-HR filed 2026-08-14

Backtest portfolio

Aureus Asset Management, LLC manages $1.65B in 13F-reported U.S. long-equity assets across 239 reported positions as of its 2026-06-30 13F-HR filing. Its largest disclosed positions are GOOGL (5.45%), AMAT (4.59%), AAPL (4.25%). Quarter over quarter (versus its 2026-03-31 filing) the fund opened 31 new positions and exited 17; 103 existing positions rose in reported value and 54 fell.

AUM is the long-equity portion reported on Form 13F-HR. Excludes short positions, cash, foreign holdings, and non-13F assets. For informational purposes only — not investment advice.

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AUM
$1.65B

Long-equity book

Holdings
239

Distinct positions

Period
2026-06-30

Filed 2026-08-14

Q/Q Activity
+31 / −17 / ↑103 / ↓54

vs 2026-03-31

Portfolio charts

Latest quarter's book, what changed, and how the portfolio has evolved across filings.

Portfolio map

Q2 26
GOOGL5.4% · -1%AMAT4.6% · -38%AAPL4.2% · +1%AMZN4.1% · -0%MSFT4.1% · -8%V3.6% · -1%AVGO3.6% · +0%SCHW3.4% · -1%LIN3.3% · -1%WCN3.3% · +4%TSM3.2% · -8%UNH3.2% · +2%NEE3.2% · -1%NVDA3.1% · +2%META2.6% · +1%TMO2.3% · -2%AXP2.3% · -0%SPGI2.1% · -4%APO2.1% · +16%ABT1.7% · -5%BX1.7% · -4%WAB1.7% · -35%CNX1.5% · -0%TXN1.3% · +76%AWK1.3% · -2%ORCL1.3% · +4%IEX1.2% · newMOG.A1.1% · +2%IVV1.1% · -6%GOOG1.0% · -1%FLS0.9% · -43%MS0.6% · +8%WMB0.6% · +3%SCI0.5% · +5%STE0.5% · +12%WCC0.5% · +3%KO0.5% · +3%A0.4% · +88%QXO0.4% · -0%JPM0.4% · +4%GLPI0.4% · +2%SPY0.4% · -4%IWM0.4% · -3%IWD0.4% · -5%CBT0.4% · 0%MU0.3% · -15%CME0.3% · +4%COHR0.3% · 0%DELL0.3% · -7%VWO0.3% · -3%MCD0.2% · +0%LLY0.2% · -16%DVN0.2% · newVEA0.2% · -2%CLOA0.2% · +6%BRK.A0.2% · 0%BRK.B0.2% · -2%SHW0.2% · -32%EEM0.2% · 0%BIV0.2% · +0%

Box size = position value; colour = change in share count vs the prior quarter (green added, red trimmed, blue new). Rows split across managers or share classes are combined. Click a box for the stock.

Sector mix

% of 13F value

Sectors from each company's SIC code; funds and ETFs grouped separately.

Biggest buys and sells

Q1 26 → Q2 26

Estimated from the change in shares held × the quarter-end price, so price moves alone don't count as buying. New and exited positions are included.

13F assets and positions

4 quarters

Total reported 13F value (bars) and number of positions (line) each quarter. Value changes include market moves.

Top positions over time

reported value

The eight largest current positions, valued at each quarter end.

Concentration

top 10 = 39.6%

Cumulative share of the portfolio held in the largest N positions.

Firm Profile & Key People

As of the firm’s regulatory filing dated Mar 31, 2026.

Assets Under Management
$8.40B
Discretionary
$2.18B
Employees
14
Accounts
954
Address
ONE WINTHROP SQUARE
BOSTON, MA 02110
Phone
(617) 728-8900
Website
Name Title / Status Ownership Type
DAVIS, THADDEUS, HALLOCK ControlMEMBER PRESIDENT CEO
since Jul 2005
25–50%Individual
BASNIGHT, TODD, AMEMBER
since Jan 2022
5–10%Individual
JONES, BRENNAN, MICHAELMEMBER, COO, CCO
since Jan 2020
10–25%Individual
KARLSSON, STEFAN, BENGT EMILMEMBER
since Jan 2014
10–25%Individual
KELLOGG, MICHAEL, WELLINGTONMEMBER
since Jan 2014
10–25%Individual
KOPROWSKI, GINA, L.MEMBER
since Jan 2015
Less than 5%Individual
SHIGUETA, CARLOS, J.MEMBER
since Jan 2016
5–10%Individual
Ownership & leadership changes · 10 filings with changes since Mar 30, 2012

From the firm’s regulatory filings, newest first. Dates are filing dates: a filing that no longer lists someone does not say when they left.

Mar 31, 2026 filing
  • No longer listedFIRESTONE, KAREN, MINDY · MEMBER CHAIRMAN · 25–50% · control person · listed since Jul 2005
  • ChangedJONES, BRENNAN, MICHAEL · title MEMBER → MEMBER, COO, CCO; ownership 5–10% → 10–25%
  • ChangedKELLOGG, MICHAEL, WELLINGTON · ownership 5–10% → 10–25%
  • ChangedKOPROWSKI, GINA, L. · title MEMBER CCO → MEMBER
Mar 28, 2024 filing
  • ChangedBASNIGHT, TODD, A · ownership Less than 5% → 5–10%
  • ChangedDAVIS, THADDEUS, HALLOCK · title MEMBER PRESIDENT → MEMBER PRESIDENT CEO; ownership 10–25% → 25–50%
  • ChangedFIRESTONE, KAREN, MINDY · title MEMBER CHAIRMAN AND CEO → MEMBER CHAIRMAN
  • ChangedJONES, BRENNAN, MICHAEL · ownership Less than 5% → 5–10%
  • ChangedKELLOGG, MICHAEL, WELLINGTON · title MEMBER & CHIEF COMPLIANCE OFFICER → MEMBER
  • ChangedKOPROWSKI, GINA, L. · title MEMBER → MEMBER CCO
  • ChangedSHIGUETA, CARLOS, J. · ownership Less than 5% → 5–10%
Mar 31, 2023 filing
  • ChangedFIRESTONE, KAREN, MINDY · ownership 50–75% → 25–50%
  • ChangedKARLSSON, STEFAN, BENGT EMIL · ownership 5–10% → 10–25%
Mar 31, 2022 filing
  • AddedBASNIGHT, TODD, A · MEMBER · Less than 5%
Mar 30, 2021 filing
  • AddedJONES, BRENNAN, MICHAEL · MEMBER · Less than 5%
  • ChangedKARLSSON, STEFAN, BENGT EMIL · ownership Less than 5% → 5–10%
Mar 28, 2017 filing
  • No longer listedJEPPSON, GEORGE, NATHANIEL · MEMBER · 10–25% · control person · listed since Jul 2005
  • ChangedKELLOGG, MICHAEL, WELLINGTON · ownership Less than 5% → 5–10%
Mar 30, 2016 filing
  • No longer listedSCUDDER, DAVID, WITHERSPOON · MEMBER · Less than 5% · control person · listed since Jul 2005
  • AddedKOPROWSKI, GINA, L. · MEMBER · Less than 5%
  • AddedSHIGUETA, CARLOS, J. · MEMBER · Less than 5%
  • ChangedDAVIS, THADDEUS, HALLOCK · title MEMBER → MEMBER PRESIDENT; now a control person
  • ChangedFIRESTONE, KAREN, MINDY · title MEMBER PRESIDENT AND CEO → MEMBER CHAIRMAN AND CEO
  • ChangedJEPPSON, GEORGE, NATHANIEL · now a control person
Apr 1, 2015 filing
  • No longer listedATKINSON, STACEY, JANE · MEMBER · Less than 5% · listed since Jul 2005
Jan 6, 2014 filing
  • AddedKARLSSON, STEFAN, BENGT EMIL · MEMBER · Less than 5%
  • AddedKELLOGG, MICHAEL, WELLINGTON · MEMBER & CHIEF COMPLIANCE OFFICER · Less than 5%
  • ChangedFIRESTONE, KAREN, MINDY · title MEMBER & CHIEF COMPLIANCE OFFICER → MEMBER PRESIDENT AND CEO
Mar 28, 2013 filing
  • ChangedFIRESTONE, KAREN, MINDY · ownership 25–50% → 50–75%
  • ChangedSCUDDER, DAVID, WITHERSPOON · ownership 25–50% → Less than 5%
Older changes (1 more filing)
Mar 30, 2012 filing (earliest on record)
  • ListedATKINSON, STACEY, JANE · MEMBER · Less than 5%
  • ListedDAVIS, THADDEUS, HALLOCK · MEMBER · 10–25%
  • ListedFIRESTONE, KAREN, MINDY · MEMBER & CHIEF COMPLIANCE OFFICER · 25–50% · control person
  • ListedJEPPSON, GEORGE, NATHANIEL · MEMBER · 10–25%
  • ListedSCUDDER, DAVID, WITHERSPOON · MEMBER · 25–50% · control person

Quarter-over-quarter changes

Changes in reported position value vs the prior 13F, so price moves count too, not just shares bought or sold.

Aureus Asset Management, LLC Holdings (2026-06-30)

Rows tagged Call or Put are options positions, not stock. Per SEC Form 13F-HR, Value shows the notional value of the underlying (shares covered × underlying price), not the option premium. Shares is the number of underlying shares covered (divide by 100 for contract count).

# Issuer Symbol CUSIP Value Weight Shares Type
1 ALPHABET INC GOOGL 02079K305 $89.6M 5.45% 250,797 SH
2 APPLIED MATLS INC AMAT 038222105 $75.5M 4.59% 104,403 SH
3 APPLE INC AAPL 037833100 $69.9M 4.25% 241,737 SH
4 AMAZON COM INC AMZN 023135106 $67.2M 4.09% 282,141 SH
5 MICROSOFT CORP MSFT 594918104 $66.9M 4.06% 179,278 SH
6 VISA INC V 92826C839 $59.2M 3.60% 172,597 SH
7 BROADCOM INC AVGO 11135F101 $58.9M 3.58% 156,049 SH
8 SCHWAB CHARLES CORP SCHW 808513105 $55.4M 3.37% 600,554 SH
9 LINDE PLC LIN G54950103 $54.9M 3.33% 105,720 SH
10 WASTE CONNECTIONS INC WCN 94106B101 $54.4M 3.30% 326,138 SH
11 TAIWAN SEMICONDUCTOR MANUFAC TSM 874039100 $53.2M 3.23% 111,481 SH
12 UNITEDHEALTH GROUP INC UNH 91324P102 $53.1M 3.23% 127,832 SH
13 NEXTERA ENERGY INC NEE 65339F101 $52.3M 3.18% 595,785 SH
14 NVIDIA CORPORATION NVDA 67066G104 $51.3M 3.11% 256,163 SH
15 META PLATFORMS INC META 30303M102 $43.2M 2.62% 76,690 SH
16 THERMO FISHER SCIENTIFIC INC TMO 883556102 $37.5M 2.28% 74,805 SH
17 AMERICAN EXPRESS CO AXP 025816109 $37.5M 2.28% 110,783 SH
18 S&P GLOBAL INC SPGI 78409V104 $34.6M 2.10% 85,032 SH
19 APOLLO GLOBAL MGMT INC APO 03769M106 $33.8M 2.05% 285,691 SH
20 ABBOTT LABORATORIES ABT 002824100 $28.5M 1.73% 313,871 SH
21 BLACKSTONE INC BX 09260D107 $28.0M 1.70% 238,299 SH
22 WABTEC WAB 929740108 $28.0M 1.70% 103,893 SH
23 CNX RES CORP CNX 12653C108 $24.2M 1.47% 712,168 SH
24 TEXAS INSTRS INC TXN 882508104 $21.7M 1.32% 72,675 SH
25 AMERICAN WTR WKS CO INC NEW AWK 030420103 $21.6M 1.31% 164,063 SH
26 ORACLE CORP ORCL 68389X105 $21.4M 1.30% 146,220 SH
27 IDEX CORP IEX 45167R104 $20.5M 1.24% 90,224 SH
28 MOOG INC MOG.A 615394202 $18.5M 1.13% 43,702 SH
29 ISHARES TR IVV 464287200 $18.0M 1.09% 24,015 SH
30 ALPHABET INC GOOG 02079K107 $16.7M 1.02% 47,389 SH
31 FLOWSERVE CORP FLS 34354P105 $15.0M 0.91% 202,821 SH
32 MORGAN STANLEY MS 617446448 $10.6M 0.65% 50,794 SH
33 WILLIAMS COS INC WMB 969457100 $10.5M 0.64% 140,693 SH
34 SERVICE CORP INTL SCI 817565104 $8.9M 0.54% 117,446 SH
35 STERIS PLC STE G8473T100 $8.9M 0.54% 42,249 SH
36 WESCO INTL INC WCC 95082P105 $8.5M 0.52% 24,654 SH
37 COCA COLA CO KO 191216100 $7.5M 0.46% 92,498 SH
38 AGILENT TECHNOLOGIES INC A 00846U101 $7.2M 0.44% 53,999 SH
39 QXO INC QXO 82846H405 $7.1M 0.43% 410,244 SH
40 JPMORGAN CHASE & CO JPM 46625H100 $6.9M 0.42% 21,189 SH
41 GAMING & LEISURE P GLPI 36467J108 $6.5M 0.39% 145,285 SH
42 STATE STR SPDR S&P 500 ETF T SPY 78462F103 $6.4M 0.39% 8,586 SH
43 ISHARES TR IWM 464287655 $6.4M 0.39% 21,304 SH
44 ISHARES TR IWD 464287598 $6.3M 0.38% 25,814 SH
45 CABOT CORP CBT 127055101 $6.1M 0.37% 67,080 SH
46 MICRON TECHNOLOGY INC MU 595112103 $5.4M 0.33% 4,664 SH
47 CME GROUP INC CME 12572Q105 $4.8M 0.29% 21,610 SH
48 COHERENT CORP COHR 19247G107 $4.6M 0.28% 11,587 SH
49 DELL TECHNOLOGIES INC DELL 24703L202 $4.5M 0.27% 10,389 SH
50 VANGUARD INTL EQUITY INDEX F VWO 922042858 $4.2M 0.25% 69,542 SH
Filing History
Period Filed AUM Holdings Accession
2026-06-30 2026-08-14 $1.65B 239 0001398344-26-014481
2026-03-31 2026-05-13 $1.50B 225 0001381296-26-000002
2025-12-31 2026-02-17 $1.57B 201 0001381296-26-000001
2025-09-30 2025-11-17 $1.54B 199 0001381296-25-000005
Filer Information
Address
ONE WINTHROP SQUARE
BOSTON, MA 02110
Phone
(617) 728-8900
Filing Manager
Aureus Asset Management, LLC
BOSTON, MA
Signatory
Connor McCarron
Trader