Institutional Manager · CIK 0001513211
Main Street Research LLC
SAUSALITO, CA · File #028-14411
Latest AUM
$1.75B
Positions
129
Top-10 Concentration
46.3%
Filings
9
Portfolio Value Over Time
2024-03
2024-06
2024-09
2024-12
2025-03
2025-06
2025-09
2025-12
Biggest QoQ Changes
Ranked by conviction flow (share change × current price) so mark-to-market moves don't dominate. Price effect column shows how much of the $ change was just the stock moving.
| Action | Issuer | Ticker / CUSIP | Δ Shares | Flow ($) | Price Effect |
|---|---|---|---|---|---|
| NEW | SPDR SERIES TRUST | 78464A870 | +360,526 | +$44.0M | $0 |
| EXITED | MERCADOLIBRE INC | 58733R102 | -15,833 | -$37.0M | $0 |
| REDUCE | T-MOBILE US INC | TMUSZ | -178,159 | -$36.2M | -$6.6M |
| EXITED | SPOTIFY TECHNOLOGY S A | L8681T102 | -50,422 | -$35.2M | $0 |
| ADD | JOHNSON & JOHNSON | JNJ | +167,933 | +$34.8M | +$245,157 |
| NEW | ISHARES INC | 464286772 | +355,461 | +$34.6M | $0 |
| NEW | ASTRAZENECA PLC | AZN | +371,217 | +$34.1M | $0 |
| ADD | CATERPILLAR INC | CAT | +56,478 | +$32.4M | +$294,913 |
| REDUCE | LINDE PLC | LIN | -72,768 | -$31.0M | -$3.6M |
| REDUCE | TRANE TECHNOLOGIES PLC | TT | -77,663 | -$30.2M | -$2.6M |
Sector Allocation
Filing History
- 13F HOLDINGS REPORTQ/E Dec 2025129 pos · $1.75B
- 13F HOLDINGS REPORTQ/E Sep 2025129 pos · $1.85B
- 13F HOLDINGS REPORTQ/E Jun 2025115 pos · $1.61B
- 13F HOLDINGS REPORTQ/E Mar 2025101 pos · $1.53B
- 13F HOLDINGS REPORTQ/E Dec 2024110 pos · $1.60B
- 13F HOLDINGS REPORTQ/E Sep 2024109 pos · $1.59B
- 13F HOLDINGS REPORTQ/E Jun 2024103 pos · $1.52B
- 13F HOLDINGS REPORTQ/E Mar 2024107 pos · $1.47B
- 13F HOLDINGS REPORTQ/E Dec 202391 pos · $970.6M
Top 20 Holdings — Dec 2025
| # | Issuer | Ticker | Shares | Value | % of Portfolio |
|---|---|---|---|---|---|
| 1 | NVIDIA CORPORATION | NVDA | 595,844 | $111.1M | 6.50% |
| 2 | ALPHABET INC | GOOG | 297,544 | $93.1M | 5.44% |
| 3 | MICROSOFT CORP | MSFT | 168,207 | $81.3M | 4.75% |
| 4 | ISHARES TR | 46434V266 | 1,907,800 | $79.1M | 4.63% |
| 5 | APPLE INC | AAPL | 290,937 | $79.1M | 4.62% |
| 6 | PALANTIR TECHNOLOGIES INC | PLTR | 440,250 | $78.3M | 4.57% |
| 7 | JPMORGAN CHASE & CO. | VYLD | 221,919 | $71.5M | 4.18% |
| 8 | BROADCOM INC | AVGO | 205,395 | $71.1M | 4.15% |
| 9 | TAIWAN SEMICONDUCTOR MFG LTD | 874039100 | 218,147 | $66.5M | 3.88% |
| 10 | VISA INC | V | 174,088 | $61.1M | 3.57% |
| 11 | ROBINHOOD MKTS INC | 770700102 | 532,399 | $60.2M | 3.52% |
| 12 | AMAZON COM INC | AMZN | 259,849 | $60.0M | 3.51% |
| 13 | META PLATFORMS INC | META | 86,547 | $57.1M | 3.34% |
| 14 | MCKESSON CORP | MCK | 67,361 | $55.3M | 3.23% |
| 15 | COSTCO WHSL CORP NEW | 22160K105 | 62,366 | $53.8M | 3.14% |
| 16 | SPDR SERIES TRUST | 78464A870 | 360,526 | $44.0M | 2.57% |
| 17 | ASML HOLDING N V | ASMLF | 40,118 | $42.9M | 2.51% |
| 18 | BARCLAYS PLC | BCLYF | 1,682,837 | $42.8M | 2.50% |
| 19 | AMPHENOL CORP NEW | 032095101 | 295,357 | $40.0M | 2.34% |
| 20 | WORLD GOLD TR | GLDW | 462,316 | $39.5M | 2.31% |