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Livermore
Livermore
ZHEN

Main Street Research LLC

SEC CIK
0001513211
Latest filing
Jul 29, 2026

The latest 13F from Main Street Research LLC covers Q2 2026 (filed Jul 29, 2026): 140 long positions worth $2.12B. The top 10 holdings make up 48.9% of the portfolio, and the largest is NVIDIA Corp (NVDA) at 6.0%. 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
13
Est. +$62.5M
Added
65
Est. +$51.1M
Reduced
52
Est. −$58.8M
Sold out
21
Est. −$57.3M

Top 5 holdings

Share of this quarter's portfolio value

  1. NVDANVIDIA Corp
    6.0%$126.1MHistory
  2. MUMicron Technology Inc
    5.9%$125.4MHistory
  3. AAPLApple Inc.
    5.5%$117.5MHistory
  4. GOOGLAlphabet Inc.
    5.3%$113.3MHistory
  5. TSMTaiwan Semiconductor Manufacturing Co Ltd
    5.1%$109.1MHistory

Share of portfolio

Top 5 holdings and the other 135 positions, by share of portfolio value

  1. NVDA6.0%
  2. MU5.9%
  3. AAPL5.5%
  4. GOOGL5.3%
  5. TSM5.1%
  6. Other 135 positions72.1%

Biggest buys

New and added positions, by estimated amount bought

  1. ROSTRoss Stores, Inc.
    +$32.1MNewHistory
  2. FTITechnipFMC plc
    +$27.4MNewHistory
  3. BCSBarclays PLC
    +$20.7MAddedHistory
  4. iShares Tr46434V266
    +$2.98MAdded
  5. TSMTaiwan Semiconductor Manufacturing Co Ltd
    +$2.52MAddedHistory

Largest weight increases

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

  1. GLWCorning Inc
    +1.68 pp3.1% → 4.8%History
  2. ROSTRoss Stores, Inc.
    +1.51 pp0.0% → 1.5%History
  3. FTITechnipFMC plc
    +1.29 pp0.0% → 1.3%History
  4. BCSBarclays PLC
    +1.01 pp1.0% → 2.1%History
  5. ASMLASML Holding NV
    +0.78 pp3.2% → 4.0%History

Biggest sells

Reduced and sold-out positions, by estimated amount sold

  1. GLDMWorld Gold Trust
    −$43.5MSold outHistory
  2. MCKMcKesson Corp
    −$29.7MReducedHistory
  3. PLTRPalantir Technologies Inc.
    −$18.2MReducedHistory
  4. IBITiShares Bitcoin Trust ETF
    −$7.53MSold outHistory
  5. PANWPalo Alto Networks Inc
    −$3.64MReducedHistory

Largest weight decreases

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

  1. GLDMWorld Gold Trust
    −2.53 pp2.5% → 0.0%History
  2. MCKMcKesson Corp
    −2.40 pp3.4% → 1.0%History
  3. PLTRPalantir Technologies Inc.
    −1.36 pp1.4% → 0.1%History
  4. IBITiShares Bitcoin Trust ETF
    −0.44 pp0.4% → 0.0%History
  5. PGProcter & Gamble Co
    −0.23 pp1.3% → 1.0%History

Metrics

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

Portfolio value
$2.12B
+$400.0M (+23.3%) vs. prior quarter
Positions
140
−8 vs. prior quarter
Top 10 concentration
48.9%
Top 10 as share of value
Turnover
5.9%
Q2 2026, one quarter
Average holding period
12.4 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 $2.12B (Q2 2026)

Q1 2021: $1.06BQ2 2021: $1.24BQ3 2021: $1.14BQ4 2021: $1.30BQ1 2022: $1.06BQ2 2022: $381.4MQ3 2022: $454.0MQ4 2022: $410.7MQ1 2023: $506.4MQ2 2023: $627.4MQ3 2023: $970.6MQ4 2023: $1.25BQ1 2024: $1.47BQ2 2024: $1.52BQ3 2024: $1.59BQ4 2024: $1.60BQ1 2025: $1.53BQ2 2025: $1.61BQ3 2025: $1.85BQ4 2025: $1.75BQ1 2026: $1.72BQ2 2026: $2.12B
Q1 2021Q2 2026
13F filings of Main Street Research LLC by quarter
QuarterFiledPositionsValueTop 3 holdingsChangesFiling
Q2 2026Jul 29, 2026140$2.12BNVDAMUAAPLvs. Q1 2026SEC
Q1 2026Apr 30, 2026148$1.72BNVDAAAPLGOOGLvs. Q4 2025SEC
Q4 2025Feb 9, 2026129$1.75BNVDAGOOGLMSFTvs. Q3 2025SEC
Q3 2025Nov 13, 2025129$1.85BNVDAAAPLMSFTvs. Q2 2025SEC
Q2 2025Aug 5, 2025115$1.61BNVDAJPMPGvs. Q1 2025SEC
Q1 2025Apr 30, 2025101$1.53BAAPLPLTRPGvs. Q4 2024SEC
Q4 2024Feb 7, 2025110$1.60BAAPLNVDAPLTRvs. Q3 2024SEC
Q3 2024Nov 12, 2024109$1.59BNVDAAAPLPGvs. Q2 2024SEC
Q2 2024Jul 29, 2024103$1.52BNVDAAAPLNVOvs. Q1 2024SEC
Q1 2024May 1, 2024107$1.47BNVDAiShares Russell 2000 ETFNVOvs. Q4 2023SEC
Q4 2023Jan 30, 2024106$1.25BAAPLiShares Russell 2000 ETFPGvs. Q3 2023SEC
Q3 2023Nov 3, 202391$970.6MAAPLPGMCKvs. Q2 2023SEC
Q2 2023Aug 8, 202393$627.4MAAPLPGMCKvs. Q1 2023SEC
Q1 2023May 1, 202391$506.4MAAPLPGNVOvs. Q4 2022SEC
Q4 2022Feb 6, 202398$410.7MPGMCKAAPLvs. Q3 2022SEC
Q3 2022Nov 14, 202297$454.0MUUPAAPLProShares Trvs. Q2 2022SEC
Q2 2022Aug 12, 202286$381.4MPGAAPLMCKvs. Q1 2022SEC
Q1 2022May 5, 2022116$1.06BAAPLPGCOSTvs. Q4 2021SEC
Q4 2021Feb 9, 2022141$1.30BAAPLPGNVDAvs. Q3 2021SEC
Q3 2021Nov 12, 2021137$1.14BAAPLPGiShares Russell 2000 ETFvs. Q2 2021SEC
Q2 2021Aug 6, 2021143$1.24BAAPLPGiShares Russell 2000 ETFvs. Q1 2021SEC
Q1 2021May 7, 2021127$1.06BPGAAPLiShares Russell 2000 ETF–SEC