Skip to content
Disclosery

ACK Asset Management LLC

Follow

13F filer, CIK 1510940, GREENWICH, CT

ACK Asset Management LLC reported $608,959,302 across 20 holdings for the quarter ended 2025-03-31, in a 13F-HR filed 2025-05-13. Its ten largest share positions make up 73.24% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001510940-25-000002

Period
2025-03-31
Reported value
$609M
Holdings
20
Top 10 weight
73.24%
New
3
Sold out
5

Largest buys vs the previous quarter

SecurityShares changeApprox. value
BIRDFnew+1,120,800$17M
SITEnew+100,000$12.1M
MRC GLOBAL INCadded+1,015,000$11.7M
MYRGadded+79,100$8.95M
LASRnew+754,000$5.86M

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
ESIexited-750,000-$19.1M
NEOGexited-1,206,796-$14.7M
APTVexited-240,000-$14.5M
BWAexited-351,400-$11.2M
DYreduced-62,700-$9.55M

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 2025

Share positions as resolved from 13F-HR 0001510940-25-000002, largest first. % of portfolio is the value over $608,959,301, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
DYDYCOM INDS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 535,500 shares; 2024Q4: 445,500 shares; 2025Q1: 382,800 shares 382,800$58.3M9.58%-62,700Timeline
ENSENERSYSQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 715,000 shares; 2024Q4: 671,024 shares; 2025Q1: 624,324 shares 624,324$57.2M9.39%-46,700Timeline
MTZMASTEC INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 772,300 shares; 2024Q4: 531,800 shares; 2025Q1: 462,700 shares 462,700$54M8.87%-69,100Timeline
ATSATS CORPORATIONQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,255,889 shares; 2024Q4: 2,093,196 shares; 2025Q1: 2,013,196 shares 2,013,196$50.2M8.24%-80,000Timeline
ATROASTRONICS CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,060,000 shares; 2024Q4: 2,060,000 shares; 2025Q1: 2,060,000 shares 2,060,000$49.8M8.18%0Timeline
JBTMJBT MAREL CORPORATIONQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 400,000 shares; 2025Q1: 369,800 shares 369,800$45.2M7.42%-30,200Timeline
MTRNMATERION CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 505,500 shares; 2024Q4: 494,800 shares; 2025Q1: 459,200 shares 459,200$37.5M6.15%-35,600Timeline
ROGROGERS CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 590,000 shares; 2024Q4: 580,000 shares; 2025Q1: 517,500 shares 517,500$34.9M5.74%-62,500Timeline
MYRGMYR GROUP INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 200,000 shares; 2025Q1: 279,100 shares 279,100$31.6M5.18%+79,100Timeline
CECOCECO ENVIRONMENTAL CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 981,200 shares; 2024Q4: 1,272,000 shares; 2025Q1: 1,201,000 shares 1,201,000$27.4M4.5%-71,000Timeline
MIRMIRION TECHNOLOGIES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 4,246,300 shares; 2024Q4: 1,815,000 shares; 2025Q1: 1,618,356 shares 1,618,356$23.5M3.85%-196,644Timeline
CLFDCLEARFIELD INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 695,000 shares; 2024Q4: 720,000 shares; 2025Q1: 687,200 shares 687,200$20.4M3.35%-32,800Timeline
CTRICENTURI HOLDINGS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 1,300,000 shares; 2025Q1: 1,220,591 shares 1,220,591$20M3.29%-79,409Timeline
MRC GLOBAL INCMRC GLOBAL INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 550,000 shares; 2025Q1: 1,565,000 shares 1,565,000$18M2.95%+1,015,000
MBCMASTERBRAND INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 650,000 shares; 2024Q4: 1,475,000 shares; 2025Q1: 1,302,500 shares 1,302,500$17M2.79%-172,500Timeline
BIRDFBIRD CONSTRUCTION INC. COMMONQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 1,120,800 shares 1,120,800$17M2.79%newTimeline
MTRXMATRIX SVC COQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 801,000 shares; 2024Q4: 1,179,901 shares; 2025Q1: 1,184,100 shares 1,184,100$14.7M2.42%+4,199Timeline
GVAGRANITE CONSTR INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 825,000 shares; 2024Q4: 284,000 shares; 2025Q1: 190,700 shares 190,700$14.4M2.36%-93,300Timeline
SITESITEONE LANDSCAPE SUPPLY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 100,000 shares 100,000$12.1M1.99%newTimeline
LASRNLIGHT INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 754,000 shares 754,000$5.86M0.96%newTimeline

Sold out in Q1 2025

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

SecurityShares beforeValue beforeType
ESIELEMENT SOLUTIONS INC750,000$19.1Mshares
NEOGNEOGEN CORP1,206,796$14.7Mshares
APTVAPTIV PLC240,000$14.5Mshares
BWABORGWARNER INC351,400$11.2Mshares
TRNSTRANSCAT INC45,000$4.76Mshares

How Q1 2025 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 0001510940-25-000002 base2025-05-13acceptance time not in the bulk data set