13D Management LLC — 13F Holdings & Portfolio

CIK 1600133 · latest 13F-HR filed 2026-05-15

13D Management LLC manages $64.5M in 13F-reported U.S. long-equity assets across 13 reported positions as of its 2026-03-31 13F-HR filing. Its largest disclosed positions are TWLO (11.85%), VSAT (11.70%), ACHC (10.66%). Quarter over quarter (versus its 2025-12-31 filing) the fund opened 1 new position, exited 4, added to 3, and trimmed 9.

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.

Loading holdings…
AUM

$64.5M

Long-equity book

Holdings

13

Distinct positions

Period

2026-03-31

Filed 2026-05-15

Q/Q Activity

+1 / −4 / ↑3 / ↓9

vs 2025-12-31

Firm Profile & Key People
Name Title / Status Ownership Type

Top Adds (vs prior quarter)

  • VIASAT INC$593.2K +8.5%
  • INTEGER HLDGS CORP$449.8K +12.2%
  • SIX FLAGS ENTERTAINMENT CORP$449.5K +15.7%
Show all 3

Top Trims

  • MERCURY SYS INC-$3.2M -41.8%
  • WORKIVA INC-$1.4M -30.9%
  • TRIPADVISOR INC-$1.2M -26.8%
  • CHARLES RIV LABS INTL INC-$1.1M -20.3%
  • TWILIO INC-$997.6K -11.5%
Show all 9

New Positions

  • ACADIA HEALTHCARE COMPANY IN$6.9M
Show all 1

Exited Positions

  • SOUTHWEST GAS HLDGS INC$5.1M
  • BILL HOLDINGS INC$4.9M
  • WEX INC$4.4M
  • LAMB WESTON HLDGS INC$3.2M
Show all 4
All Holdings

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 TWILIO INC TWLO 90138F102 $7.6M 11.85% 60,755 SH
2 VIASAT INC VSAT 92552V100 $7.5M 11.70% 164,750 SH
3 ACADIA HEALTHCARE COMPANY IN ACHC 00404A109 $6.9M 10.66% 294,000 SH
4 PEARSON PLC PSO 705015105 $6.0M 9.33% 458,338 SH
5 AUTOLIV INC ALV 052800109 $5.9M 9.10% 55,839 SH
6 CHARLES RIV LABS INTL INC CRL 159864107 $4.5M 6.90% 25,800 SH
7 MERCURY SYS INC MRCY 589378108 $4.4M 6.83% 60,462 SH
8 EXELIXIS INC EXEL 30161Q104 $4.3M 6.74% 101,335 SH
9 INTEGER HLDGS CORP ITGR 45826H109 $4.1M 6.41% 47,000 SH
10 ETSY INC ETSY 29786A106 $3.6M 5.57% 71,836 SH
11 SIX FLAGS ENTERTAINMENT CORP FUN 83001C108 $3.3M 5.13% 186,500 SH
12 TRIPADVISOR INC TRIP 896945201 $3.2M 4.96% 300,000 SH
13 WORKIVA INC WK 98139A105 $3.1M 4.81% 52,000 SH
Filing History
Period Filed AUM Holdings Accession
2026-03-31 2026-05-15 $64.5M 13 0001172661-26-002041
2025-12-31 2026-02-17 $84.0M 16 0001172661-26-000830
2025-09-30 2025-11-14 $104.3M 18 0001172661-25-004791