FRONTIER CAPITAL MANAGEMENT CO LLC — 13F Holdings & Portfolio
CIK 351173 · latest 13F-HR filed 2026-08-14
FRONTIER CAPITAL MANAGEMENT CO LLC manages $10.73B in 13F-reported U.S. long-equity assets across 300 reported positions as of its 2026-06-30 13F-HR filing. Its largest disclosed positions are FTAI (2.98%), GVA (1.65%), ALK (1.65%). Quarter over quarter (versus its 2026-03-31 filing) the fund opened 33 new positions and exited 24; 134 existing positions rose in reported value and 99 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
$10.73B
Long-equity book
Holdings
300
Distinct positions
Period
2026-06-30
Filed 2026-08-14
Q/Q Activity
+33 / −24 / ↑134 / ↓99
vs 2026-03-31
Portfolio charts
Latest quarter's book, what changed, and how the portfolio has evolved across filings.
Portfolio map
Q2 26FTAI3.0% · +11%GVA1.6% · -6%ALK1.6% · +0%AAOI1.3% · +243%AKAM1.3% · +10%ASH1.2% · +5%LSCC1.2% · +36%BPOP1.1% · -10%MDB1.0% · +56%UTHR1.0% · -18%KNX1.0% · -32%EXP1.0% · -25%LRN1.0% · -23%XPO1.0% · -23%BBIO1.0% · +43%LBRT0.9% · +49%SANM0.9% · -41%UCTT0.9% · -63%RARE0.9% · +30%PODD0.9% · +261%MOD0.9% · +68%FLS0.9% · +167%KEX0.8% · +3%ALGT0.8% · +27%P0.8% · +19%AMTM0.8% · -16%KYMR0.8% · -2%INSM0.8% · +69%ATI0.8% · -40%RNST0.7% · +4%ALAB0.7% · -78%RCL0.7% · -2%PVLA0.7% · +28%DT0.7% · newINDI0.7% · -17%ADC0.7% · -14%LUNR0.6% · -10%JAZZ0.6% · -46%SAIA0.6% · -17%ENTG0.6% · -53%FBP0.6% · -17%CRCL0.6% · -35%HUBB0.6% · +379%AXSM0.6% · +25%FLEX0.6% · +6%WTFC0.6% · -17%TDW0.6% · -17%ATMU0.6% · +56%JBL0.5% · -8%BLDR0.5% · -24%SNOW0.5% · +218%TRVI0.5% · +54%GENI0.5% · +90%BWIN0.5% · +90%VERA0.5% · +135%URGN0.5% · +15%MKSI0.5% · -25%GTX0.5% · -45%ELAN0.5% · -10%EBC0.5% · -18%
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 valueSectors from each company's SIC code; funds and ETFs grouped separately.
Biggest buys and sells
Q1 26 → Q2 26Estimated 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 quartersTotal reported 13F value (bars) and number of positions (line) each quarter. Value changes include market moves.
Top positions over time
reported valueThe eight largest current positions, valued at each quarter end.
Concentration
top 10 = 14.5%Cumulative share of the portfolio held in the largest N positions.
Firm Profile & Key People
As of the firm’s regulatory filing dated Sep 1, 2026.
Assets Under Management
$9.60B
Discretionary
$9.60B
Employees
38
Accounts
55
Address
1 LIBERTY SQUARE
10TH FLOOR
BOSTON, MA 02109
10TH FLOOR
BOSTON, MA 02109
Phone
(617) 261-0777
| Name | Title / Status | Ownership | Type |
|---|---|---|---|
| BERGGREN, JILLIAN, PATRICIA Control | CONTROLLER since Mar 2019 | Less than 5% | Individual |
| JANKOWSKI, SARAH, JEAN Control | CHIEF OPERATING OFFICER/MANAGING PARTNER since Jun 1996 | Less than 5% | Individual |
| PHAY, ROBERT, E Control | CHIEF COMPLIANCE OFFICER AND GENERAL COUNSEL since Aug 2019 | Less than 5% | Individual |
| FCMC HOLDINGS LLC | MANAGER MEMBER since Jan 2000 | 75% or more | Domestic Entity |
| AFFILIATED MANAGERS GROUP, INC. Control Indirect owner via AMG FCMC HOLDINGS, LLC | MANAGER MEMBER since Jun 2014 | 75% or more | Domestic Entity |
| AMG FCMC HOLDINGS, LLC Control Indirect owner via FCMC HOLDINGS LLC | MANAGING MEMBER since Jun 2014 | 75% or more | Domestic Entity |
Ownership & leadership changes · 11 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 listedTEICHNER, WILLIAM, ALLEN · MANAGING PARTNER · Less than 5% · control person · listed since Sep 1992
Mar 28, 2024 filing
- ChangedFCMC HOLDINGS LLC · ownership 50–75% → 75% or more
Mar 31, 2021 filing
- No longer listedCAVARRETTA, MICHAEL, ANTHONY · CHAIRMAN · Less than 5% · control person · listed since Jul 1988
Mar 30, 2020 filing
- No longer listedKNIGHTLY, STEPHEN, MICHAEL · PRESIDENT/MGMT. CMTE. MEMBER · Less than 5% · control person · listed since Sep 1992
- ChangedBERGGREN, JILLIAN, PATRICIA · title CHIEF FINANCIAL OFFICER → CONTROLLER
- ChangedCAVARRETTA, MICHAEL, ANTHONY · title CHAIRMAN/MGMT. CMTE. MEMBER → CHAIRMAN; ownership 5–10% → Less than 5%
- ChangedJANKOWSKI, SARAH, JEAN · title CHIEF OPERATING OFFICER/MGMT. CMTE. MEMBER → CHIEF OPERATING OFFICER/MANAGING PARTNER
- ChangedTEICHNER, WILLIAM, ALLEN · title EXECUTIVE VICE PRESIDENT/MGMT. CMTE. MEMBER → MANAGING PARTNER
Aug 8, 2019 filing
- No longer listedBALLOU, WILLIAM, JOHN · CHIEF COMPLIANCE OFFICER AND GENERAL COUNSEL · Less than 5% · control person · listed since Apr 2019
- No longer listedDUNCAN, THOMAS, WILLIAM · DIRECTOR OF RESEARCH / MGMT. CMTE. MEMBER · Less than 5% · control person · listed since Jan 2016
- AddedPHAY, ROBERT, E · CHIEF COMPLIANCE OFFICER AND GENERAL COUNSEL · Less than 5% · control person
- AddedTEICHNER, WILLIAM, ALLEN · EXECUTIVE VICE PRESIDENT/MGMT. CMTE. MEMBER · Less than 5% · control person
Apr 17, 2019 filing
- No longer listedHULL, JULIANNE · CHIEF COMPLIANCE OFFICER AND GENERAL COUNSEL · Less than 5% · control person · listed since Oct 2018
- Listed againBALLOU, WILLIAM, JOHN · CHIEF COMPLIANCE OFFICER AND GENERAL COUNSEL · Less than 5% · control person
Mar 28, 2019 filing
- No longer listedBINDER, RICHARD, HOWARD · SENIOR VP/CFO · Less than 5% · control person · listed since Mar 1992
- AddedBERGGREN, JILLIAN, PATRICIA · CHIEF FINANCIAL OFFICER · Less than 5% · control person
- ChangedJANKOWSKI, SARAH, JEAN · title CHIEF ADMINISTRATIVE OFFICER/MGMT. CMTE. MEMBER → CHIEF OPERATING OFFICER/MGMT. CMTE. MEMBER
Oct 15, 2018 filing
- No longer listedBALLOU, WILLIAM, JOHN · CHIEF COUNSEL AND CHIEF COMPLIANCE OFFICER/MGMT. CMTE. MEMBER · Less than 5% · control person · listed since Apr 2002
- AddedHULL, JULIANNE · CHIEF COMPLIANCE OFFICER AND GENERAL COUNSEL · Less than 5% · control person
Mar 30, 2016 filing
- AddedDUNCAN, THOMAS, WILLIAM · DIRECTOR OF RESEARCH / MGMT. CMTE. MEMBER · Less than 5% · control person
Mar 30, 2015 filing
- No longer listedAFFILIATED MANAGERS GROUP, INC. · MANAGER MEMBER · 75% or more · indirect via FCMC HOLDINGS LLC · control person · listed since Jan 2000
- AddedAFFILIATED MANAGERS GROUP, INC. · MANAGER MEMBER · 75% or more · indirect via AMG FCMC HOLDINGS, LLC · control person
- AddedAMG FCMC HOLDINGS, LLC · MANAGING MEMBER · 75% or more · indirect via FCMC HOLDINGS LLC · control person
Older changes (2 more filings)
Apr 1, 2013 filing
- ChangedFCMC HOLDINGS LLC · no longer a control person
Mar 30, 2012 filing (earliest on record)
- ListedAFFILIATED MANAGERS GROUP, INC. · MANAGER MEMBER · 75% or more · indirect via FCMC HOLDINGS LLC · control person
- ListedBALLOU, WILLIAM, JOHN · CHIEF COUNSEL AND CHIEF COMPLIANCE OFFICER/MGMT. CMTE. MEMBER · Less than 5% · control person
- ListedBINDER, RICHARD, HOWARD · SENIOR VP/CFO · Less than 5% · control person
- ListedCAVARRETTA, MICHAEL, ANTHONY · CHAIRMAN/MGMT. CMTE. MEMBER · 5–10% · control person
- ListedFCMC HOLDINGS LLC · MANAGER MEMBER · 50–75% · control person
- ListedJANKOWSKI, SARAH, JEAN · CHIEF ADMINISTRATIVE OFFICER/MGMT. CMTE. MEMBER · Less than 5% · control person
- ListedKNIGHTLY, STEPHEN, MICHAEL · PRESIDENT/MGMT. CMTE. MEMBER · Less than 5% · 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)
- APPLIED OPTOELECTRONICS INC$120.5M +501.2%
- LATTICE SEMICONDUCTOR CORP$69.6M +123.9%
- FTAI AVIATION LTD$59.9M +23.0%
- MONGODB INC$59.8M +113.9%
- INSULET CORP$58.6M +161.8%
Top Trims
- DARLING INGREDIENTS INC-$108.5M -71.5%
- CIRCLE INTERNET GROUP INC-$84.8M -57.4%
- SILA REALTY TRUST INC-$52.4M -82.1%
- APOGEE THERAPEUTICS INC-$49.3M -55.0%
- AMENTUM HOLDINGS INC-$42.9M -33.4%
New Positions
- DYNATRACE INC$71.8M
- PRIMORIS SVCS CORP$46.5M
- STANDARDAERO INC$43.3M
- ALKERMES PLC$34.6M
- ETORO GROUP LTD$32.8M
Exited Positions
- MARVELL TECHNOLOGY INC$53.6M
- NUVALENT INC$40.5M
- DIODES INC$40.4M
- QUIDELORTHO CORP$28.8M
- DOMINOS PIZZA INC$22.5M
FRONTIER CAPITAL MANAGEMENT CO 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 | FTAI AVIATION LTD | FTAI | G3730V105 | $320.2M | 2.98% | 1,183,492 | SH |
| 2 | GRANITE CONSTR INC | GVA | 387328107 | $176.9M | 1.65% | 1,118,881 | SH |
| 3 | ALASKA AIR GROUP INC | ALK | 011659109 | $176.7M | 1.65% | 3,384,643 | SH |
| 4 | APPLIED OPTOELECTRONICS INC | AAOI | 03823U102 | $144.5M | 1.35% | 975,318 | SH |
| 5 | AKAMAI TECHNOLOGIES INC | AKAM | 00971T101 | $134.4M | 1.25% | 1,136,573 | SH |
| 6 | ASHLAND INC | ASH | 044186104 | $131.8M | 1.23% | 1,999,908 | SH |
| 7 | LATTICE SEMICONDUCTOR CORP | LSCC | 518415104 | $125.7M | 1.17% | 821,848 | SH |
| 8 | POPULAR INC | BPOP | 733174700 | $119.1M | 1.11% | 725,227 | SH |
| 9 | MONGODB INC | MDB | 60937P106 | $112.2M | 1.05% | 334,098 | SH |
| 10 | UNITED THERAPEUTICS CORP DEL | UTHR | 91307C102 | $112.1M | 1.04% | 206,808 | SH |
| 11 | KNIGHT-SWIFT TRANSN HLDGS IN | KNX | 499049104 | $109.9M | 1.02% | 1,410,955 | SH |
| 12 | EAGLE MATLS INC | EXP | 26969P108 | $103.2M | 0.96% | 458,621 | SH |
| 13 | STRIDE INC | LRN | 86333M108 | $102.8M | 0.96% | 1,191,710 | SH |
| 14 | XPO INC | XPO | 983793100 | $102.6M | 0.96% | 499,601 | SH |
| 15 | BRIDGEBIO PHARMA INC | BBIO | 10806X102 | $102.3M | 0.95% | 1,373,057 | SH |
| 16 | LIBERTY ENERGY INC | LBRT | 53115L104 | $97.4M | 0.91% | 3,720,666 | SH |
| 17 | SANMINA CORP | SANM | 801056102 | $95.7M | 0.89% | 378,111 | SH |
| 18 | ULTRA CLEAN HLDGS INC | UCTT | 90385V107 | $95.2M | 0.89% | 667,532 | SH |
| 19 | ULTRAGENYX PHARMACEUTICAL IN | RARE | 90400D108 | $95.1M | 0.89% | 2,847,936 | SH |
| 20 | INSULET CORP | PODD | 45784P101 | $94.8M | 0.88% | 622,506 | SH |
| 21 | MODINE MFG CO | MOD | 607828100 | $91.8M | 0.86% | 343,868 | SH |
| 22 | FLOWSERVE CORP | FLS | 34354P105 | $91.5M | 0.85% | 1,233,291 | SH |
| 23 | KIRBY CORP | KEX | 497266106 | $90.6M | 0.84% | 666,554 | SH |
| 24 | ALLEGIANT TRAVEL CO | ALGT | 01748X102 | $90.0M | 0.84% | 765,347 | SH |
| 25 | EVERPURE INC | P | 74624M102 | $88.2M | 0.82% | 1,120,040 | SH |
| 26 | AMENTUM HOLDINGS INC | AMTM | 023939101 | $85.7M | 0.80% | 4,143,971 | SH |
| 27 | KYMERA THERAPEUTICS INC | KYMR | 501575104 | $85.0M | 0.79% | 740,866 | SH |
| 28 | INSMED INC | INSM | 457669307 | $84.8M | 0.79% | 795,242 | SH |
| 29 | ATI INC | ATI | 01741R102 | $82.8M | 0.77% | 419,968 | SH |
| 30 | RENASANT CORP | RNST | 75970E107 | $75.7M | 0.71% | 1,778,953 | SH |
| 31 | ASTERA LABS INC | ALAB | 04626A103 | $74.7M | 0.70% | 154,601 | SH |
| 32 | ROYAL CARIBBEAN GROUP | RCL | V7780T103 | $74.3M | 0.69% | 233,963 | SH |
| 33 | PALVELLA THERAPEUTICS INC NE | PVLA | 697947109 | $73.2M | 0.68% | 478,833 | SH |
| 34 | DYNATRACE INC | DT | 268150109 | $71.8M | 0.67% | 1,635,587 | SH |
| 35 | INDIE SEMICONDUCTOR INC | INDI | 45569U101 | $71.5M | 0.67% | 15,914,169 | SH |
| 36 | AGREE RLTY CORP | ADC | 008492100 | $71.4M | 0.67% | 943,005 | SH |
| 37 | INTUITIVE MACHINES INC | LUNR | 46125A100 | $67.9M | 0.63% | 3,173,434 | SH |
| 38 | JAZZ PHARMACEUTICALS PLC | JAZZ | G50871105 | $66.8M | 0.62% | 277,279 | SH |
| 39 | SAIA INC | SAIA | 78709Y105 | $63.8M | 0.59% | 151,477 | SH |
| 40 | ENTEGRIS INC | ENTG | 29362U104 | $63.3M | 0.59% | 351,950 | SH |
| 41 | FIRST BANCORP CORPORATION | FBP | 318672706 | $63.1M | 0.59% | 2,422,265 | SH |
| 42 | CIRCLE INTERNET GROUP INC | CRCL | 172573107 | $62.9M | 0.59% | 1,004,783 | SH |
| 43 | HUBBELL INC | HUBB | 443510607 | $62.8M | 0.59% | 119,997 | SH |
| 44 | AXSOME THERAPEUTICS INC. | AXSM | 05464T104 | $62.2M | 0.58% | 254,280 | SH |
| 45 | FLEX LTD | FLEX | Y2573F102 | $61.9M | 0.58% | 382,135 | SH |
| 46 | WINTRUST FINL CORP | WTFC | 97650W108 | $61.8M | 0.58% | 384,593 | SH |
| 47 | TIDEWATER INC NEW | TDW | 88642R109 | $59.6M | 0.56% | 894,796 | SH |
| 48 | ATMUS FILTRATION TECHNOLOGIE | ATMU | 04956D107 | $59.0M | 0.55% | 1,157,930 | SH |
| 49 | JABIL INC | JBL | 466313103 | $58.7M | 0.55% | 152,187 | SH |
| 50 | BUILDERS FIRSTSOURCE INC | BLDR | 12008R107 | $58.3M | 0.54% | 651,389 | SH |
Filing History
| Period | Filed | AUM | Holdings | Accession |
|---|---|---|---|---|
| 2026-06-30 | 2026-08-14 | $10.73B | 300 | 0001172661-26-003509 |
| 2026-03-31 | 2026-05-15 | $9.73B | 291 | 0001172661-26-002082 |
| 2025-12-31 | 2026-02-17 | $9.42B | 295 | 0001172661-26-000845 |
| 2025-09-30 | 2025-11-14 | $11.15B | 297 | 0001172661-25-004908 |
Filer Information
Address
99 SUMMER STBOSTON, MA 02110
Phone
(617) 261-0777
Filing Manager
FRONTIER CAPITAL MANAGEMENT CO LLC
Boston, MA
Signatory
Robert E. Phay, Jr.
Chief Compliance Officer