Main Street Research LLC

Fundamental diversified ★Signal CIK 1513211
League rank
#153
in Fundamental diversified · #666 overall
Long book
$1.72B
Q1 2026
Positions
148
Top-10 weight
45%
concentration
Last quarter
+19.3%
SPY +14.8%
Turnover
27%
of book per quarter

Strategy in plain words

auto-generated from filings

Main Street Research LLC is a diversified fundamental manager, running a $1.72B US long book across 148 positions.

The portfolio is moderately concentrated (top 10 ≈ 45% of the book). The portfolio is actively managed, with meaningful quarterly turnover. Current anchor positions: NVIDIA CORP, APPLE INC, ALPHABET INC-CL A, ISHARES INTERNATIONAL SMALL, TAIWAN SEMICONDUCTOR-SP ADR.

Over the last 9 quarters its long book ran on average 1.1pp per quarter ahead of the S&P 500, beating the index in 5 of 9 quarters. We rate its filings as signal-bearing: position changes reflect genuine views.

Implied long-book return vs S&P 500

methodology: positions priced quarterly, no shorts/options
Fund long book S&P 500
Q1 2024
+5.7%
Q2 2024
+3.1%
Q3 2024
+4.1%
Q4 2024
-4.3%
Q1 2025
+17.4%
Q2 2025
+7.7%
Q3 2025
+0.1%
Q4 2025
-3.2%
Q1 2026
+19.3%

Sector allocation

Technology
45%
Consumer discretionary
16%
Industrials
16%
Financials
9%
Healthcare
7%
Materials
3%
Other
2%
Services media
1%

Long book by quarter

$1.47B
Q1 2024
$1.52B
Q2 2024
$1.59B
Q3 2024
$1.60B
Q4 2024
$1.53B
Q1 2025
$1.61B
Q2 2025
$1.85B
Q3 2025
$1.75B
Q4 2025
$1.72B
Q1 2026

What does Main Street own?

Q1 2026 13F
CompanySectorSharesValue% of bookChange
NVDA NVIDIA CORPTechnology620.8K$108.3M6.3%+4.2%
AAPL APPLE INCTechnology403.6K$102.4M6.0%+38.7%
GOOGL ALPHABET INC-CL ATechnology311.8K$89.7M5.2%+4.8%
JPM JPMORGAN CHASE & COFinancials223.8K$65.8M3.8%+0.8%
AVGO BROADCOM INCTechnology212.4K$65.7M3.8%+3.4%
MCK MCKESSON CORPConsumer discretionary67.8K$58.6M3.4%+0.6%
AMZN AMAZON.COM INCConsumer discretionary269.2K$56.1M3.3%+3.6%
ASML ASML HOLDING NV-NY REG SHSIndustrials41.7K$55.1M3.2%+3.9%
GLW CORNING INCIndustrials387.7K$52.7M3.1%New
COST COSTCO WHOLESALE CORPConsumer discretionary46.1K$46.0M2.7%-26.0%
JNJ JOHNSON & JOHNSONHealthcare186.9K$45.7M2.7%+4.2%
GEV GE VERNOVA INCIndustrials50.7K$44.2M2.6%+3.1%
CAT CATERPILLAR INCIndustrials61.1K$43.3M2.5%+2.6%
WMT WALMART INCConsumer discretionary344.9K$42.9M2.5%+1.9%
CCJ CAMECO CORPMaterials389.1K$42.3M2.5%+1.9%
META META PLATFORMS INC-CLASS ATechnology71.0K$40.6M2.4%-18.0%
APH AMPHENOL CORP-CL ATechnology301.0K$38.0M2.2%+1.9%
AZN ASTRAZENECA PLCHealthcare190.6K$37.6M2.2%New
MU MICRON TECHNOLOGY INCTechnology109.1K$36.9M2.1%+1949.8%
RY ROYAL BANK OF CANADAFinancials222.6K$36.0M2.1%New
KEYS KEYSIGHT TECHNOLOGIES INTechnology112.9K$31.9M1.9%New
MSFT MICROSOFT CORPTechnology67.5K$25.0M1.5%-59.8%
PLTR PALANTIR TECHNOLOGIES INC-ATechnology167.6K$24.5M1.4%-61.9%
PG PROCTER & GAMBLE CO/THEOther151.6K$21.9M1.3%+0.4%
FICO FAIR ISAAC CORPServices media8.5K$9.0M0.5%+239.6%
GOOG ALPHABET INC-CL CTechnology23.4K$6.7M0.4%+16.7%
BRK/B BERKSHIRE HATHAWAY INC-CL BFinancials12.0K$5.7M0.3%-1.1%
PANW PALO ALTO NETWORKS INCTechnology34.0K$5.5M0.3%+157.1%
MCD MCDONALD'S CORPConsumer discretionary15.5K$4.8M0.3%-16.7%
TSLA TESLA INCIndustrials12.3K$4.6M0.3%-3.2%
SCHW SCHWAB (CHARLES) CORPFinancials46.4K$4.4M0.3%+45.9%
ANET ARISTA NETWORKS INCTechnology35.0K$4.3M0.2%New
XOM EXXON MOBIL CORPEnergy23.9K$4.1M0.2%+3.1%
WFC WELLS FARGO & COFinancials46.9K$3.7M0.2%+136.2%
BRK/A BERKSHIRE HATHAWAY INC-CL AFinancials5$3.6M0.2%Held
CVX CHEVRON CORPEnergy16.9K$3.5M0.2%+77.0%
ADSK AUTODESK INCTechnology14.4K$3.4M0.2%+0.8%
V VISA INC-CLASS A SHARESServices media10.2K$3.1M0.2%-94.1%
LLY ELI LILLY & COHealthcare2.9K$2.7M0.2%+104.9%
ABBV ABBVIE INCHealthcare10.3K$2.2M0.1%+9.7%
CRM SALESFORCE INCTechnology6.9K$1.3M0.1%+8.8%
RTX RTX CORPIndustrials6.1K$1.2M0.1%+10.4%
MRK MERCK & CO. INC.Healthcare9.5K$1.1M0.1%+22.3%
MMM 3M COHealthcare7.9K$1.1M0.1%-2.3%
DIS WALT DISNEY CO/THEServices media10.7K$1.0M0.1%New
UNP UNION PACIFIC CORPIndustrials4.1K$1.0M0.1%+76.3%
CLX CLOROX COMPANYOther9.5K$988K0.1%+4.5%
PHM PULTEGROUP INCIndustrials7.4K$868K0.1%New
CRUS CIRRUS LOGIC INCTechnology5.7K$829K0.0%New
UBER UBER TECHNOLOGIES INCServices media11.5K$827K0.0%-97.4%

13F filing history

PeriodFormFiledEntriesReported valueFlagsSource
Q1 202613F-HRApr 30, 2026148$1.72B canonicalSEC ↗
Q4 202513F-HRFeb 9, 2026129$1.75B canonicalSEC ↗
Q3 202513F-HRNov 13, 2025129$1.85B canonicalSEC ↗
Q2 202513F-HRAug 5, 2025115$1.61B canonicalSEC ↗
Q1 202513F-HRApr 30, 2025101$1.53B canonicalSEC ↗
Q4 202413F-HRFeb 7, 2025110$1.60B canonicalSEC ↗
Q3 202413F-HRNov 12, 2024109$1.59B canonicalSEC ↗
Q2 202413F-HRJul 29, 2024103$1.52B canonicalSEC ↗
Q1 202413F-HRMay 1, 2024107$1.47B canonicalSEC ↗