ATMU · Insider trading · 13F holders · Congress trades
Atmus Filtration Technologies Inc. (ATMU)
Who is buying and selling ATMU: company insiders on SEC Form 4, hedge funds and superinvestors on Form 13F, and members of Congress under the STOCK Act. Every figure links to the filing or page it comes from.
- 13F filers holding
- 13
- Insider buys, 90 days
- $100K
- Insider sales, 90 days
- $197K
- Congress trades, 12 months
- 0
ATMU at a glance
- Between Aug 1, 2026 and Oct 29, 2026, 2 ATMU insiders filed 1 open-market purchase worth $100K and 1 sale worth $197K on SEC Form 4.
- 13 13F filers hold ATMU among their 50 largest positions, worth $500.3M combined, including Ricky Sandler. The biggest bets by portfolio weight are Mangrove Partners Im, LLC (4.1%), Marathon Partners Equity Management, LLC (3.9%) and Medina Value Partners, LLC (3.2%). In their latest 13Fs, 0 managers opened a new position and 5 added to one.
- No member of Congress has disclosed a trade in ATMU.
- ATMU last closed at $46.46 on Oct 29, 2026.
ATMU insider trading
Between Aug 1, 2026 and Oct 29, 2026, 2 ATMU insiders filed 1 open-market purchase worth $100K and 1 sale worth $197K on SEC Form 4.
| Filed | Insider | Role | Trade | Shares | Price | Value | Form 4 |
|---|---|---|---|---|---|---|---|
| Aug 18, 2026 | Swan Renee | Chief People Officer | Sale | 3,870 | $50.89 | $197K | SEC |
| Aug 13, 2026 | Macadam Stephen E. | Director | Buy | 2,000 | $49.78 | $100K | SEC |
Who owns ATMU? Hedge funds and superinvestors
13 13F filers hold ATMU among their 50 largest positions, worth $500.3M combined, including Ricky Sandler. The biggest bets by portfolio weight are Mangrove Partners Im, LLC (4.1%), Marathon Partners Equity Management, LLC (3.9%) and Medina Value Partners, LLC (3.2%). In their latest 13Fs, 0 managers opened a new position and 5 added to one.
Superinvestors holding ATMU: Ricky Sandler 1.7%
| Manager | % of portfolio | Value | Shares | Last quarter | 13F |
|---|---|---|---|---|---|
| Channing Capital Management, LLCInstitutional asset manager | 2.0% | $88.0M | 1,725,956 | +24.5% shares | Q2 2026 |
| Ricky SandlerHedge fund | 1.7% | $72.8M | 1,281,995 | -66.5% shares | Q1 2026 |
| Westwood Holdings Group IncInvestment manager | 0.5% | $71.2M | 1,397,165 | — | Q2 2026 |
| Mangrove Partners Im, LLCHedge fund | 4.1% | $61.8M | 1,211,236 | -7.9% shares | Q2 2026 |
| Frontier Capital Management Co LLCInstitutional asset manager | 0.6% | $59.0M | 1,157,930 | — | Q2 2026 |
| Port Capital LLCHedge fund | 2.2% | $52.7M | 1,034,293 | +13.8% shares | Q2 2026 |
| Royce & Associates LPMutual fund manager | 0.4% | $50.7M | 995,247 | +28.0% shares | Q2 2026 |
| Medina Value Partners, LLCHedge fund | 3.2% | $16.3M | 318,986 | +40.9% shares | Q2 2026 |
| Altrinsic Global Advisors LLCHedge fund | 0.6% | $15.1M | 296,885 | +26.5% shares | Q2 2026 |
| Prentiss Smith & Co IncWealth manager | 2.9% | $5.1M | 116,931 | -3.0% shares | Q3 2026 |
| Marathon Partners Equity Management, LLCHedge fund | 3.9% | $3.9M | 77,000 | +2.7% shares | Q2 2026 |
| Riverwater Partners LLCWealth manager | 0.7% | $2.2M | 43,911 | -17.4% shares | Q2 2026 |
| Charter Oak Advisors LPHedge fund | 0.8% | $1.3M | 26,464 | +0.0% shares | Q2 2026 |
Each manager counts with its latest 13F (Q3 2026: 1, Q2 2026: 11, Q1 2026: 1). Screen ATMU in the grand portfolio →
ATMU stock trades by members of Congress
No member of Congress has disclosed a trade in ATMU.
ATMU questions and answers
Are insiders buying ATMU stock?
Between Aug 1, 2026 and Oct 29, 2026, 2 ATMU insiders filed 1 open-market purchase worth $100K and 1 sale worth $197K on SEC Form 4.
Which hedge funds own ATMU?
13 13F filers hold ATMU among their 50 largest positions, worth $500.3M combined, including Ricky Sandler. The biggest bets by portfolio weight are Mangrove Partners Im, LLC (4.1%), Marathon Partners Equity Management, LLC (3.9%) and Medina Value Partners, LLC (3.2%). In their latest 13Fs, 0 managers opened a new position and 5 added to one.
Has Congress traded ATMU?
No member of Congress has disclosed a trade in ATMU.
Who is the largest holder of ATMU?
Among 13F filers, Channing Capital Management, LLC reports the largest ATMU position, $88.0M (1,725,956 shares) in its Q2 2026 13F. The biggest bet by portfolio weight is Mangrove Partners Im, LLC's: 4.1% of its portfolio.
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