Mattern Capital Management
Mattern Capital Management reported 166 stocks worth $856M in its 13F filing for Q3 2026, filed Nov 2, 2026. Its largest holdings are AAPL (2.8%), MSFT (2.3%) and GWW (1.6%). Compared with Q2 2026, the fund opened new positions in DUHP, TJX and GE, added to AVGO, LIN and WEC, trimmed AAPL, MSFT and GWW and sold out of NKE, XOM and OKE.
Holdings
| # | Stock | Value | Weight | Shares | Change | Shares, 8 qtrs | Held |
|---|---|---|---|---|---|---|---|
| 1 |  AAPL Apple Inc | $23.7M | 2.8% | 71K | −5,228 (−7%) | 8 of 8 | |
| 2 |  MSFT Microsoft Corp | $19.7M | 2.3% | 38K | −2,682 (−7%) | 8 of 8 | |
| 3 |  GWW Grainger W W Inc | $14M | 1.6% | 11K | −608 (−5%) | 8 of 8 | |
| 4 |  COR Cencora Inc | $13.1M | 1.5% | 44K | −3,118 (−7%) | 8 of 8 | |
| 5 |  COST Costco Whsl Corp New | $13.1M | 1.5% | 14K | −16 (−0%) | 8 of 8 | |
| 6 |  AVGO Broadcom Inc | $12.5M | 1.5% | 36K | +535 (+2%) | 8 of 8 | |
| 7 |  UNH Unitedhealth Group Inc | $12.5M | 1.4% | 34K | −1,321 (−4%) | 8 of 8 | |
| 8 |  ADP Automatic Data Processing in | $12.3M | 1.4% | 48K | −2,610 (−5%) | 8 of 8 | |
| 9 |  AFL Aflac Inc | $12M | 1.4% | 108K | −2,565 (−2%) | 8 of 8 | |
| 10 |  FDS Factset Resh Sys Inc | $11.8M | 1.4% | 44K | −3,071 (−7%) | 8 of 8 |
Positions at Sep 30, 2026, as reported. Change is against the fund's Q2 2026 filing; weight is the share of the fund's reported stocks.
Sold out
held in Q2 2026, gone in Q3 2026| Stock | Value last quarter | Shares sold |
|---|---|---|
 NKE Nike Inc | $7.9M | 193K |
DIMENSIONAL ETF TRUST | $3.2M | 76K |
 XOM Exxon Mobil Corp | $507K | 3,708 |
 OKE Oneok Inc New | $328K | 3,767 |
 IEMG Ishares Inc | $324K | 3,915 |
🔒 Free account: see all 9.
Reported value
last 8 quartersThe value of the US stocks the fund reported, at quarter end prices. It moves with the market as well as with buying and selling.
Filings for Q3 2026
straight from the SEC| Filed | Form | Quarter | |
|---|---|---|---|
| Nov 2, 2026 | 13F-HR | Q3 2026 | SEC filing ↗ |
Other superinvestors
All hedge fund holdings →Mattern Capital Management 13F FAQ
What does Mattern Capital Management own?
Mattern Capital Management reported 166 stocks worth $856M in its 13F filing for Q3 2026, filed Nov 2, 2026. Its largest holdings are AAPL (2.8%), MSFT (2.3%) and GWW (1.6%). The table above lists every position in the filing (the top 10 without an account).
What did Mattern Capital Management buy and sell in Q3 2026?
Compared with Q2 2026: 9 new positions, 61 added to, 67 trimmed and 9 sold out. New positions include DUHP, TJX and GE. It sold all of NKE, XOM and OKE.
When will Mattern Capital Management file its next 13F?
Holdings as of Dec 31, 2026 are due by Feb 15, 2027. The filing appears on this page within minutes of reaching the SEC.
How much is Mattern Capital Management's portfolio worth?
The Q3 2026 filing reports $856M in US stocks. That leaves out cash, bonds, short positions and most foreign holdings, so the fund's total assets are usually larger.
For informational and educational purposes only. Not investment advice, and not a recommendation to buy or sell any security. Holdings come from the fund's SEC Form 13F filings as reported and show positions at the end of the quarter, up to 45 days before the filing. The fund may have changed its positions since. A 13F leaves out short positions, cash, bonds and most foreign holdings. See all hedge fund holdings.