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Livermore
Livermore
ZHEN

Mattern Capital Management, LLC

SEC CIK
0001803227
Latest filing
Jul 24, 2026

The latest 13F from Mattern Capital Management, LLC covers Q2 2026 (filed Jul 24, 2026): 166 long positions worth $856.7M. The top 10 holdings make up 17.0% of the portfolio, and the largest is Apple Inc. (AAPL) at 2.6%. Livermore has 22 filings on Form 13F from this institution, going back to Q1 2021.

What changed in Q2 2026

Share counts compared with Q1 2026: how many positions were new, added to, reduced or sold out, and the biggest buys and sells. Dollar amounts are estimated at the quarter-end prices implied by the filing.

Full comparison
New
3
Est. +$726.9K
Added
92
Est. +$55.1M
Reduced
43
Est. −$42.9M
Sold out
7
Est. −$7.82M

Top 5 holdings

Share of this quarter's portfolio value

  1. AAPLApple Inc.
    2.6%$22.1MHistory
  2. GWWW.W. Grainger, Inc.
    1.9%$16.1MHistory
  3. MSFTMicrosoft Corp
    1.8%$15.3MHistory
  4. UNHUnitedHealth Group Inc
    1.7%$14.6MHistory
  5. COSTCostco Wholesale Corp
    1.6%$13.4MHistory

Biggest buys

New and added positions, by estimated amount bought

  1. JPMJPMorgan Chase & Co
    +$8.68MAddedHistory
  2. TSCOTractor Supply Co
    +$2.75MAddedHistory
  3. NKENIKE, Inc.
    +$2.39MAddedHistory
  4. ZTSZoetis Inc.
    +$2.14MAddedHistory
  5. BDXBecton Dickinson & Co
    +$2.13MAddedHistory

Largest weight increases

New and added positions, by percentage points of the portfolio gained

  1. JPMJPMorgan Chase & Co
    +1.03 pp0.2% → 1.2%History
  2. CSCOCisco Systems, Inc.
    +0.52 pp0.9% → 1.5%History
  3. APHAmphenol Corp
    +0.49 pp0.8% → 1.3%History
  4. LLYEli Lilly & Co
    +0.37 pp1.1% → 1.4%History
  5. VVisa Inc.
    +0.21 pp1.0% → 1.2%History

Biggest sells

Reduced and sold-out positions, by estimated amount sold

  1. PSXPhillips 66
    −$8.74MReducedHistory
  2. PPGPPG Industries Inc
    −$8.59MReducedHistory
  3. CBSHCommerce Bancshares Inc
    −$7.40MReducedHistory
  4. MKCMcCormick & Co Inc
    −$6.24MSold outHistory
  5. FRTFederal Realty Investment Trust
    −$4.78MReducedHistory

Largest weight decreases

Reduced and sold-out positions, by percentage points of the portfolio lost

  1. PSXPhillips 66
    −1.21 pp1.9% → 0.7%History
  2. PPGPPG Industries Inc
    −0.90 pp1.0% → 0.1%History
  3. MKCMcCormick & Co Inc
    −0.75 pp0.7% → 0.0%History
  4. CBSHCommerce Bancshares Inc
    −0.73 pp1.0% → 0.2%History
  5. ORealty Income Corp
    −0.53 pp0.7% → 0.1%History

Metrics

13F metrics for Q2 2026, computed only from the numbers in the filings. Definitions below.

Portfolio value
$856.7M
+$21.9M (+2.6%) vs. prior quarter
Positions
166
−4 vs. prior quarter
Top 10 concentration
17.0%
Top 10 as share of value
Turnover
6.0%
Q2 2026, one quarter
Average holding period
17.5 quarters
Weighted by value

How these are calculated

  • Portfolio value: the market value of all long positions in the 13F, as reported at quarter end, excluding options.
  • Top 10 concentration: the combined value of the 10 largest positions as a share of portfolio value.
  • Turnover: the smaller of this quarter's estimated purchases and estimated sales, divided by the average of this and last quarter's portfolio value. Estimates multiply the change in shares by the quarter-end price implied by the filing (market value divided by shares); new positions use this quarter's value and sold-out positions last quarter's. Only positions reported in shares count, and it is not calculated when the previous quarter was not filed.
  • Average holding period: how many consecutive quarters each current position has been held (including this one; a quarter without the position or without a filing starts the count over), weighted by this quarter's value. Counting starts with the first 13F in Livermore (Q1 2021), so positions held before then are understated.

13F filings by quarter

22 quarters, going back to Q1 2021. Bars show each quarter's 13F portfolio value; quarters without a filing are left blank.

Peak $856.7M (Q2 2026)

Q1 2021: $462.4MQ2 2021: $505.8MQ3 2021: $506.6MQ4 2021: $571.7MQ1 2022: $559.3MQ2 2022: $505.7MQ3 2022: $480.0MQ4 2022: $540.8MQ1 2023: $566.9MQ2 2023: $616.1MQ3 2023: $618.2MQ4 2023: $687.9MQ1 2024: $736.5MQ2 2024: $723.8MQ3 2024: $794.6MQ4 2024: $767.4MQ1 2025: $785.4MQ2 2025: $832.4MQ3 2025: $850.6MQ4 2025: $846.9MQ1 2026: $834.9MQ2 2026: $856.7M
Q1 2021Q2 2026
13F filings of Mattern Capital Management, LLC by quarter
QuarterFiledPositionsValueTop 3 holdingsChangesFiling
Q2 2026Jul 24, 2026166$856.7MAAPLGWWMSFTvs. Q1 2026SEC
Q1 2026May 4, 2026170$834.9MAAPLPSXMSFTvs. Q4 2025SEC
Q4 2025Jan 29, 2026170$846.9MAAPLMSFTWMTvs. Q3 2025SEC
Q3 2025Oct 21, 2025172$850.6MAAPLMSFTWMTvs. Q2 2025SEC
Q2 2025Jul 21, 2025170$832.4MMSFTAAPLWMTvs. Q1 2025SEC
Q1 2025Apr 23, 2025163$785.4MAAPLBROMSFTvs. Q4 2024SEC
Q4 2024Feb 3, 2025160$767.4MAAPLMSFTCOSTvs. Q3 2024SEC
Q3 2024Oct 24, 2024156$794.6MAAPLMSFTLOWvs. Q2 2024SEC
Q2 2024Aug 2, 2024157$723.8MAAPLMSFTCOSTvs. Q1 2024SEC
Q1 2024May 14, 2024157$736.5MMSFTAAPLPSXvs. Q4 2023SEC
Q4 2023Feb 14, 2024136$687.9MAAPLMSFTPSXvs. Q3 2023SEC
Q3 2023Nov 8, 2023135$618.2MAAPLMSFTPSXvs. Q2 2023SEC
Q2 2023Aug 8, 2023134$616.1MAAPLMSFTLOWvs. Q1 2023SEC
Q1 2023May 12, 2023120$566.9MAAPLMSFTLOWvs. Q4 2022SEC
Q4 2022Feb 6, 2023120$540.8MAAPLMSFTLOWvs. Q3 2022SEC
Q3 2022Nov 8, 2022118$480.0MAAPLLOWMSFTvs. Q2 2022SEC
Q2 2022Aug 8, 2022118$505.7MAAPLMSFTLOWvs. Q1 2022SEC
Q1 2022May 3, 2022122$559.3MAAPLMSFTLOWvs. Q4 2021SEC
Q4 2021Feb 3, 2022117$571.7MAAPLMSFTLOWvs. Q3 2021SEC
Q3 2021Nov 1, 2021114$506.6MAAPLMSFTLOWvs. Q2 2021SEC
Q2 2021Aug 3, 2021116$505.8MAAPLMSFTLOWvs. Q1 2021SEC
Q1 2021May 17, 2021109$462.4MAAPLLOWMSFT–SEC