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Algoma Steel Group Inc.

ASTL
Exchange
Nasdaq
Industry
Steel Works, Blast Furnaces & Rolling Mills (Coke Ovens)
SEC CIK
0001860805

No open-market purchases or sales by Algoma Steel Group Inc. insiders were filed in the last 90 days; 95 institutions reported holding it in 13F filings for Q2 2026, worth $291.8M in total; no superinvestor holds it.

Holders of 5% or more of ASTL

Holders whose latest Schedule 13D or 13G filing reports 5% or more of Algoma Steel Group Inc., largest stake first. The change is against the holder's previous filing.

Holders of 5% or more of ASTL
HolderLatest formStakeChangeFirst filedLatest filingFiling
Maple Rock Capital Partners Inc.13G/A15.10%15.9M shares+1.80 ppfrom 13.30%Feb 14, 20238 filingsMay 15, 2026SEC
MMCAP International Inc. SPC13G/A10.40%11.0M shares−1.80 ppfrom 12.20%Feb 20, 20249 filingsAug 14, 2026SEC
Stoney Lonesome HF LP13G/A5.40%5.86M shares+0.20 ppfrom 5.20%Apr 10, 20252 filingsAug 14, 2025SEC
Donald Smith & Co., Inc.13G5.00%5.28M shares−0.80 ppfrom 5.80%Feb 9, 202310 filingsAug 11, 2026SEC

Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.

13D and 13G filings

42 Schedule 13D and 13G filings on Algoma Steel Group Inc., newest first, including old-format filings without a stake.

Schedule 13D and 13G filings on ASTL
Filed (ET)FilerFormStakeChangeEvent dateFiling
Aug 14, 20264:08 PM ETMMCAP International Inc. SPCand 1 other13G/A10.40%11.0M shares−1.80 ppfrom 12.20%Jun 30, 2026SEC
Aug 11, 202611:58 AM ETDonald Smith & Co., Inc.and 1 other13G5.00%5.28M shares−0.80 ppfrom 5.80%Jun 30, 2026SEC
May 15, 20265:08 PM ETMaple Rock Capital Partners Inc.and 1 other13G/A15.10%15.9M shares+1.80 ppfrom 13.30%Mar 31, 2026SEC
May 15, 20264:29 PM ETMMCAP International Inc. SPCand 1 other13G/A12.20%12.8M shares+1.30 ppfrom 10.90%Mar 31, 2026SEC
May 13, 20262:50 PM ETDonald Smith & Co., Inc.and 1 other13G5.80%6.03M shares+0.20 ppfrom 5.60%Mar 31, 2026SEC
Feb 17, 20264:00 PM ETMMCAP International Inc. SPCand 1 other13G/A10.90%11.5M shares+0.90 ppfrom 10.00%Dec 31, 2025SEC
Feb 12, 20269:21 AM ETDonald Smith & Co., Inc.and 1 other13G5.60%5.86M shares−0.10 ppfrom 5.70%Dec 31, 2025SEC
Nov 20, 20252:57 PM ETMMCAP International Inc. SPCand 1 other13G/A10.00%10.5M shares+2.30 ppfrom 7.70%Nov 18, 2025SEC
Nov 14, 20254:40 PM ETMMCAP International Inc. SPCand 1 other13G/A7.70%8.08M shares+0.80 ppfrom 6.90%Sep 30, 2025SEC
Nov 12, 202511:59 AM ETDonald Smith & Co., Inc.and 1 other13G5.70%5.94M shares−0.10 ppfrom 5.80%Sep 30, 2025SEC
Nov 7, 20254:12 PM ETMaple Rock Capital Partners Inc.and 1 other13G/A13.30%14.0M shares+3.40 ppfrom 9.90%Oct 31, 2025SEC
Sep 23, 20254:15 PM ETZekelman Industries, Inc.and 1 other13D/A3.08%3.23M shares–Below 5%Sep 10, 2025SEC
Aug 28, 20256:57 PM ETMaple Rock Capital Partners Inc.and 1 other13G9.90%10.4M shares0.00 ppfrom 9.90%Aug 28, 2025SEC
Aug 14, 20258:48 PM ETMaple Rock Capital Partners Inc.and 1 other13D/A9.90%10.4M shares+2.70 ppfrom 7.20%Aug 12, 2025SEC
Aug 14, 20254:32 PM ETMMCAP International Inc. SPCand 1 other13G/A6.90%7.22M shares+0.60 ppfrom 6.30%Jun 30, 2025SEC
Aug 14, 20254:12 PM ETStoney Lonesome HF LPand 4 others13G/A5.40%5.86M shares+0.20 ppfrom 5.20%Jun 30, 2025SEC
Aug 13, 20252:57 PM ETDonald Smith & Co., Inc.and 1 other13G5.80%6.04M shares−1.90 ppfrom 7.70%Jun 30, 2025SEC
May 15, 20254:47 PM ETMMCAP International Inc. SPCand 1 other13G/A6.30%6.64M shares–Mar 31, 2025SEC
May 13, 20252:02 PM ETDonald Smith & Co., Inc.and 1 other13G7.70%8.09M shares−0.10 ppfrom 7.80%Mar 31, 2025SEC
May 5, 20257:07 PM ETMaple Rock Capital Partners Inc.and 1 other13D/A7.20%7.55M shares–May 1, 2025SEC
Apr 29, 20259:27 AM ETBlackRock, Inc.13G/A3.70%3.84M shares–Below 5%Mar 31, 2025SEC
Apr 10, 20251:19 PM ETStoney Lonesome HF LPand 2 others13G5.20%5.46M sharesNewApr 4, 2025SEC
Feb 13, 20252:13 PM ETDonald Smith & Co., Inc.and 1 other13G7.80%8.07M shares–Dec 31, 2024SEC
Nov 8, 2024BlackRock, Inc.13GOld format–––SEC
Nov 5, 2024MMCAP International Inc. SPC13G/AOld format–––SEC
Oct 25, 2024Maple Rock Capital Partners Inc.13DOld format–––SEC
Oct 25, 2024Donald Smith & Co., Inc.13GOld format–––SEC
Oct 22, 2024BlackRock, Inc.13GOld format–New–SEC
Jul 31, 2024Zekelman Industries, Inc.13DOld format–New–SEC
Feb 20, 2024MMCAP International Inc. SPC13GOld format–New–SEC
Feb 14, 2024Maple Rock Capital Partners Inc.13G/AOld format–––SEC
Feb 13, 2024Contrarian Capital Management, L.L.C.13G/AOld format–––SEC
Feb 12, 2024Polus Capital Management Ltd13G/AOld format–––SEC
Feb 5, 2024Donald Smith & Co., Inc.13GOld format–––SEC
Feb 14, 2023Maple Rock Capital Partners Inc.13GOld format–New–SEC
Feb 13, 2023Contrarian Capital Management, L.L.C.13G/AOld format–––SEC
Feb 9, 2023Donald Smith & Co., Inc.13GOld format–New–SEC
Jan 12, 2023Polus Capital Management Ltd13GOld format–New–SEC
Aug 5, 2022Bain Capital Credit, LP13D/AOld format–––SEC
Apr 13, 2022Bain Capital Credit, LP13DOld format–New–SEC
Feb 14, 2022Contrarian Capital Management, L.L.C.13GOld format–New–SEC
Feb 14, 2022Barclays PLC13GOld format–New–SEC

Form 144: proposed insider sales

3 notices from officers, directors and other affiliates planning to sell Algoma Steel Group Inc. shares, newest first.

Form 144 notices for ASTL
Filed (ET)SellerShares to sellMarket valuePlanned saleBrokerFiling
Sep 16, 20244:35 PM ETSgro DavidDirector200.0K$2.04MSep 16, 2024Fidelity Brokerage Services LLCSEC
Dec 19, 20233:46 PM ETSgro DavidDirector230.0K$2.14MDec 19, 2023Fidelity Brokerage Services LLCSEC
Nov 13, 20231:58 PM ETSgro DavidDirector275.0K$1.98MNov 13, 2023Fidelity Brokerage Services LLCSEC