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Portolan Capital Management, LLC — 13F Holdings & Portfolio

CIK 1350290 · latest 13F-HR filed 2026-08-14

Backtest portfolio

Portolan Capital Management, LLC manages $2.67B in 13F-reported U.S. long-equity assets across 148 reported positions as of its 2026-06-30 13F-HR filing. Its largest disclosed positions are VPG (5.66%), VIRT (4.78%), TTMI (3.56%). Quarter over quarter (versus its 2026-03-31 filing) the fund opened 36 new positions and exited 32; 62 existing positions rose in reported value and 39 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
$2.67B

Long-equity book

Holdings
148

Distinct positions

Period
2026-06-30

Filed 2026-08-14

Q/Q Activity
+36 / −32 / ↑62 / ↓39

vs 2026-03-31

Portfolio charts

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

Portfolio map

Q2 26
VPG5.7% · -1%VIRT4.8% · +77%TTMI3.6% · -30%MOD3.1% · -24%QLYS2.7% · +122%FOUR2.0% · +420%MEC1.8% · +58%ENVA1.8% · +146%SMTC1.8% · -11%CLS1.7% · -36%UTHR1.7% · +28%GENI1.6% · +152%POWL1.6% · +92%PENG1.6% · newDAVE1.5% · -0%FLEX1.4% · -48%ALNT1.4% · +11%PRCH1.4% · +14%AKAM1.4% · -27%CADL1.3% · +21%TLN1.3% · +11%RRX1.2% · +155%LNTH1.2% · -31%BIIB1.2% · +21%VECO1.1% · +58%LUXE1.1% · +8%ZETA1.1% · +209%CLBT1.1% · -11%SRAD1.0% · newGOOS1.0% · -14%BAND1.0% · newWRBY1.0% · +68%KTB0.9% · newOSK0.9% · +767%ECPG0.9% · newTWLO0.9% · +54%SEZL0.9% · +94%RELY0.9% · +46%ACMR0.8% · +113%ESI0.8% · +112%NOK0.8% · -31%BB0.8% · newIFF0.8% · newPLSE0.8% · +3%MOG.A0.8% · +67%REAX0.8% · -24%CDNA0.7% · +101%PARR0.7% · -51%VSH0.7% · newTTWO0.7% · +125%GTES0.7% · newMAMA0.7% · -16%KRUS0.7% · +0%SANM0.6% · +150%PKE0.6% · +9%GHM0.6% · +32%BELFB0.6% · -10%ONON0.6% · +118%AS0.6% · +27%COHU0.6% · new

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 = 29%

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

Firm Profile & Key People

As of the firm’s regulatory filing dated Apr 15, 2026.

Assets Under Management
$2.02B
Discretionary
$2.02B
Employees
12
Accounts
20
Address
TWO INTERNATIONAL PLACE
SUITE 2630
BOSTON, MA 02110
Phone
(617) 753-6400
Website
Name Title / Status Ownership Type
MCCABE, GEORGE, FREDERIC ControlCHIEF INVESTMENT OFFICER, MANAGING DIRECTOR, AND SOLE MEMBER
since Dec 2004
75% or moreIndividual
BONNER, NANCY, JEANCHIEF ADMINISTRATIVE OFFICER
since Nov 2014
Less than 5%Individual
FLAHERTY, BETSY, HOCHADELCHIEF COMPLIANCE OFFICER
since Jan 2021
Less than 5%Individual
NARDONE, CHRISTOPHER, SAMUELCHIEF FINANCIAL OFFICER AND CHIEF OPERATING OFFICER
since Nov 2014
Less than 5%Individual
Ownership & leadership changes · 4 filings with changes since Feb 14, 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, 2023 filing
  • ChangedBONNER, NANCY, JEAN · title CHIEF OPERATING OFFICER → CHIEF ADMINISTRATIVE OFFICER
  • ChangedNARDONE, CHRISTOPHER, SAMUEL · title CHIEF FINANCIAL OFFICER → CHIEF FINANCIAL OFFICER AND CHIEF OPERATING OFFICER
Jan 14, 2021 filing
  • AddedFLAHERTY, BETSY, HOCHADEL · CHIEF COMPLIANCE OFFICER · Less than 5%
  • ChangedNARDONE, CHRISTOPHER, SAMUEL · title CHIEF COMPLIANCE OFFICER AND CHIEF FINANCIAL OFFICER → CHIEF FINANCIAL OFFICER
Nov 7, 2014 filing
  • No longer listedKOUTSOURAKIS, DEMETRIOS · CHIEF OPERATING OFFICER · Less than 5% · listed since Apr 2013
  • ChangedBONNER, NANCY, JEAN · title CHIEF COMPLIANCE OFFICER → CHIEF OPERATING OFFICER
  • ChangedNARDONE, CHRISTOPHER, SAMUEL · title CHIEF FINANCIAL OFFICER → CHIEF COMPLIANCE OFFICER AND CHIEF FINANCIAL OFFICER
Mar 31, 2014 filing
  • AddedKOUTSOURAKIS, DEMETRIOS · CHIEF OPERATING OFFICER · Less than 5%
  • AddedNARDONE, CHRISTOPHER, SAMUEL · CHIEF FINANCIAL OFFICER · Less than 5%
Feb 14, 2012 filing (earliest on record)
  • ListedBONNER, NANCY, JEAN · CHIEF COMPLIANCE OFFICER · Less than 5%
  • ListedMCCABE, GEORGE, FREDERIC · CHIEF INVESTMENT OFFICER, MANAGING DIRECTOR, AND SOLE MEMBER · 75% or more · 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.

Top Adds (vs prior quarter)

Show all 62 →

Top Trims

Show all 39 →

New Positions

Show all 36 →

Exited Positions

Show all 32 →

Portolan Capital 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 VISHAY PRECISION GROUP INC VPG 92835K103 $151.1M 5.66% 1,008,167 SH
2 VIRTU FINL INC VIRT 928254101 $127.6M 4.78% 2,142,215 SH
3 TTM TECHNOLOGIES INC TTMI 87305R109 $95.0M 3.56% 507,838 SH
4 MODINE MFG CO MOD 607828100 $83.8M 3.14% 313,683 SH
5 QUALYS INC QLYS 74758T303 $72.8M 2.73% 529,807 SH
6 SHIFT4 PMTS INC FOUR 82452J109 $54.2M 2.03% 1,114,116 SH
7 MAYVILLE ENGR CO INC MEC 578605107 $48.7M 1.82% 1,299,256 SH
8 ENOVA INTL INC ENVA 29357K103 $47.9M 1.79% 198,795 SH
9 SEMTECH CORP SMTC 816850101 $47.7M 1.79% 294,619 SH
10 CELESTICA INC CLS 15101Q207 $46.3M 1.73% 126,856 SH
11 UNITED THERAPEUTICS CORP DEL UTHR 91307C102 $44.2M 1.65% 81,518 SH
12 GENIUS SPORTS LIMITED GENI G3934V109 $42.6M 1.59% 7,025,809 SH
13 POWELL INDS INC POWL 739128106 $41.7M 1.56% 145,631 SH
14 PENGUIN SOLUTIONS INC PENG 706915105 $41.5M 1.55% 546,173 SH
15 DAVE INC DAVE 23834J201 $39.2M 1.47% 105,338 SH
16 FLEX LTD FLEX Y2573F102 $37.1M 1.39% 229,027 SH
17 ALLIENT INC ALNT 019330109 $37.0M 1.39% 359,685 SH
18 PORCH GROUP INC PRCH 733245104 $36.9M 1.38% 2,456,451 SH
19 AKAMAI TECHNOLOGIES INC AKAM 00971T101 $36.7M 1.37% 310,361 SH
20 CANDEL THERAPEUTICS INC CADL 137404109 $36.0M 1.35% 3,490,398 SH
21 TALEN ENERGY CORP TLN 87422Q109 $34.7M 1.30% 90,312 SH
22 REGAL REXNORD CORPORATION RRX 758750103 $32.8M 1.23% 137,498 SH
23 LANTHEUS HLDGS INC LNTH 516544103 $32.0M 1.20% 288,691 SH
24 BIOGEN INC BIIB 09062X103 $30.9M 1.16% 142,856 SH
25 VEECO INSTRS INC DEL VECO 922417100 $30.4M 1.14% 401,639 SH
26 LUXEXPERIENCE BV LUXE 55406W103 $30.1M 1.13% 4,053,147 SH
27 ZETA GLOBAL HOLDINGS CORP ZETA 98956A105 $29.6M 1.11% 1,502,738 SH
28 CELLEBRITE DI LTD CLBT M2197Q107 $28.2M 1.06% 1,932,514 SH
29 SPORTRADAR GROUP AG SRAD H8088L103 $27.2M 1.02% 1,819,949 SH
30 CANADA GOOSE HLDGS INC GOOS 135086106 $26.2M 0.98% 2,750,523 SH
31 BANDWIDTH INC BAND 05988J103 $26.1M 0.98% 412,701 SH
32 WARBY PARKER INC WRBY 93403J106 $25.6M 0.96% 843,862 SH
33 KONTOOR BRANDS INC KTB 50050N103 $24.3M 0.91% 292,115 SH
34 OSHKOSH CORP OSK 688239201 $24.2M 0.91% 157,641 SH
35 ENCORE CAP GROUP INC ECPG 292554102 $23.9M 0.89% 255,715 SH
36 TWILIO INC TWLO 90138F102 $23.8M 0.89% 115,397 SH
37 SEZZLE INC SEZL 78435P105 $23.3M 0.87% 135,743 SH
38 REMITLY GLOBAL INC RELY 75960P104 $22.8M 0.85% 1,017,592 SH
39 ACM RESH INC ACMR 00108J109 $22.5M 0.84% 177,432 SH
40 ELEMENT SOLUTIONS INC ESI 28618M106 $22.4M 0.84% 469,213 SH
41 NOKIA CORP NOK 654902204 $21.9M 0.82% 1,645,761 SH
42 BLACKBERRY LTD BB 09228F103 $21.7M 0.81% 1,714,461 SH
43 INTERNATIONAL FLAVORS&FRAGRA IFF 459506101 $21.3M 0.80% 269,229 SH
44 PULSE BIOSCIENCES INC PLSE 74587B101 $20.9M 0.78% 753,333 SH
45 MOOG INC MOG.A 615394202 $20.9M 0.78% 49,274 SH
46 THE REAL BROKERAGE INC REAX 75585H206 $20.1M 0.75% 11,042,364 SH
47 CAREDX INC CDNA 14167L103 $19.5M 0.73% 684,805 SH
48 PAR PAC HOLDINGS INC PARR 69888T207 $19.2M 0.72% 341,863 SH
49 VISHAY INTERTECHNOLOGY INC VSH 928298108 $18.9M 0.71% 351,515 SH
50 TAKE-TWO INTERACTIVE SOFTWAR TTWO 874054109 $18.1M 0.68% 72,487 SH
Filing History
Period Filed AUM Holdings Accession
2026-06-30 2026-08-14 $2.67B 148 0001104659-26-096980
2026-03-31 2026-05-15 $1.88B 144 0001104659-26-062488
2025-12-31 2026-02-17 $1.87B 155 0001104659-26-016304
2025-09-30 2025-11-13 $1.85B 119 0001104659-25-111284
Filer Information
Address
2 INTERNATIONAL PLACE, 26TH FLOOR
BOSTON, MA 02110
Phone
(617) 753-6400
Filing Manager
Portolan Capital Management, LLC
BOSTON, MA
Signatory
Betsy Flaherty
Chief Compliance Officer