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13D Management LLC

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13F filer, CIK 1600133, New York, NY

13D Management LLC reported $64,496,951 across 13 holdings for the quarter ended 2026-03-31, in a 13F-HR filed 2026-05-15. Its ten largest share positions make up 85.1% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001172661-26-002041

Period
2026-03-31
Reported value
$64.5M
Holdings
13
Top 10 weight
85.1%
New
1
Sold out
4

Largest buys vs the previous quarter

SecurityShares changeApprox. value
ACHCnew+294,000$6.88M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
SWXexited-63,798-$5.11M
BILLexited-90,000-$4.91M
WEXexited-29,350-$4.37M
LWexited-76,001-$3.18M
MRCYreduced-43,300-$3.16M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Holdings, Q1 2026

Share positions as resolved from 13F-HR 0001172661-26-002041, largest first. % of portfolio is the value over $64,496,951, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
TWLOTWILIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 98,893 shares; 2024Q4: 90,757 shares; 2025Q1: 62,540 shares; 2025Q2: 60,755 shares; 2025Q3: 60,755 shares; 2025Q4: 60,755 shares; 2026Q1: 60,755 shares 60,755$7.64M11.85%0Timeline
VSATVIASAT INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 267,000 shares; 2025Q4: 201,750 shares; 2026Q1: 164,750 shares 164,750$7.55M11.7%-37,000Timeline
ACHCACADIA HEALTHCARE COMPANY INQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: 294,000 shares 294,000$6.88M10.66%newTimeline
PSOPEARSON PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 512,732 shares; 2024Q4: 513,759 shares; 2025Q1: 471,167 shares; 2025Q2: 458,338 shares; 2025Q3: 458,338 shares; 2025Q4: 458,338 shares; 2026Q1: 458,338 shares 458,338$6.02M9.33%0Timeline
ALVAUTOLIV INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 54,047 shares; 2024Q4: 62,589 shares; 2025Q1: 57,400 shares; 2025Q2: 55,839 shares; 2025Q3: 55,839 shares; 2025Q4: 55,839 shares; 2026Q1: 55,839 shares 55,839$5.87M9.1%0Timeline
CRLCHARLES RIV LABS INTL INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 28,000 shares; 2025Q3: 28,000 shares; 2025Q4: 28,000 shares; 2026Q1: 25,800 shares 25,800$4.45M6.9%-2,200Timeline
MRCYMERCURY SYS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 131,508 shares; 2024Q4: 221,015 shares; 2025Q1: 202,701 shares; 2025Q2: 137,012 shares; 2025Q3: 137,012 shares; 2025Q4: 103,762 shares; 2026Q1: 60,462 shares 60,462$4.41M6.83%-43,300Timeline
EXELEXELIXIS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 360,575 shares; 2024Q4: 228,610 shares; 2025Q1: 147,506 shares; 2025Q2: 143,335 shares; 2025Q3: 120,335 shares; 2025Q4: 120,335 shares; 2026Q1: 101,335 shares 101,335$4.35M6.74%-19,000Timeline
ITGRINTEGER HLDGS CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 47,000 shares; 2026Q1: 47,000 shares 47,000$4.14M6.41%0Timeline
ETSYETSY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 87,817 shares; 2024Q4: 87,258 shares; 2025Q1: 80,025 shares; 2025Q2: 77,836 shares; 2025Q3: 77,836 shares; 2025Q4: 71,836 shares; 2026Q1: 71,836 shares 71,836$3.59M5.57%0Timeline
FUNSIX FLAGS ENTERTAINMENT CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 186,500 shares; 2026Q1: 186,500 shares 186,500$3.31M5.13%0Timeline
TRIPTRIPADVISOR INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 300,000 shares; 2025Q4: 300,000 shares; 2026Q1: 300,000 shares 300,000$3.2M4.96%0Timeline
WKWORKIVA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 52,000 shares; 2026Q1: 52,000 shares 52,000$3.1M4.81%0Timeline

Sold out in Q1 2026

Positions in the previous quarter's report that this quarter's report no longer lists.

SecurityShares beforeValue beforeType
SWXSOUTHWEST GAS HLDGS INC63,798$5.11Mshares
BILLBILL HOLDINGS INC90,000$4.91Mshares
WEXWEX INC29,350$4.37Mshares
LWLAMB WESTON HLDGS INC76,001$3.18Mshares

How Q1 2026 was built

Available 13F filings of this filer for the quarter and their roles: the base report is the latest original or restatement, NEW HOLDINGS amendments filed after it are added (method).

FilingRoleAmendmentFiledAcceptedIngested
13F-HR 0001172661-26-002041 base2026-05-15acceptance time not in the bulk data set