# EDGAR Filing Document

**Accession Number:** 0001513211
**File Stem:** 0001420506-25-003188
**Filing Date:** 2025-11
**Character Count:** 16009
**Document Hash:** 1f29aa468deb7cca666c2522537bf73c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001420506-25-003188.hdr.sgml**: 20251113

**ACCESSION NUMBER**: 0001420506-25-003188

**CONFORMED SUBMISSION TYPE**: 13F-HR

**PUBLIC DOCUMENT COUNT**: 2

**CONFORMED PERIOD OF REPORT**: 20250930

**FILED AS OF DATE**: 20251113

**DATE AS OF CHANGE**: 20251113

**EFFECTIVENESS DATE**: 20251113

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Main Street Research LLC
- **CENTRAL INDEX KEY:** 0001513211

**ORGANIZATION NAME:**
- **EIN:** 680313978
- **STATE OF INCORPORATION:** CT
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 13F-HR
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 028-14411
- **FILM NUMBER:** 251477010

**BUSINESS ADDRESS:**
- **STREET 1:** 342 MAIN STREET
- **CITY:** LAKEVILLE
- **STATE:** CT
- **ZIP:** 06039
- **BUSINESS PHONE:** 860-435-2350

**MAIL ADDRESS:**
- **STREET 1:** 30 LIBERTY SHIP WAY, SUITE 3330
- **CITY:** SAUSALITO
- **STATE:** CA
- **ZIP:** 94965

### FORM 13F COVER PAGE

**Report for the Calendar Year or Quarter Ended:** 09-30-2025

**Check here if Amendment** [ ] **Amendment Number:** 

**This Amendment (Check only one.):** [ ] is a restatement.

[ ] adds new holdings entries.

**Institutional Investment Manager Filing this Report:**

**Name:** Main Street Research LLC<br>**Address:** 30 LIBERTY SHIP WAY SUITE 3330<br>SAUSALITO, CA 94965

**Form 13F File Number:** 028-14411

The institutional investment manager filing this report and the person by whom it is signed hereby represent that the person signing the report is authorized to submit it, that all information contained herein is true, correct and complete, and that it is understood that all required items, statements, schedules, lists, and tables, are considered integral parts of this form.

**Person Signing this Report on Behalf of Reporting Manager:**

**Name:** Natalie McMahon<br>**Title:** Chief Compliance Officer<br>**Phone:** 860-435-2350

**Signature, Place, and Date of Signing:**

Natalie McMahon Chief Compliance Officer  SAUSALITO, CA  11-13-2025<br>[Signature]  [City, State]  [Date]

**Report Type (Check only one.):**

[x] **13F HOLDINGS REPORT.** (Check here if all holdings of this reporting manager are reported in this report.)

[ ] **13F NOTICE.** (Check here if no holdings are reported in this report, and all holdings are reported by other reporting manager(s).)

[ ] **13F COMBINATION REPORT.** (Check here if a portion of the holdings for this reporting manager are reported in this report and a portion are reported by other reporting manager(s).)

### Form 13F Summary Page

**Report Summary:**

**Number of Other Included Managers:** 0

**Form 13F Information Table Entry Total:** 129

**Form 13F Information Table Value Total:** $1850822523

      (round to nearest dollar)

**List of Other Included Managers:**

Provide a numbered list of the name(s) and Form 13F file number(s) of all institutional investment managers with respect to which this report is filed, other than the manager filing this report.

[If there are no entries in this list, state “NONE” and omit the column headings and list entries.]

**NONE**

### FORM 13F INFORMATION TABLE

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| NAME OF ISSUER | TITLE OF CLASS | CUSIP | FIGI | VALUE (x$1000) | SHRS OR PRN AMT | SH/PRN | PUT/CALL | INVESTMENT DISCRETION | OTHER MANAGER | VOTING AUTHORITY | VOTING AUTHORITY | VOTING AUTHORITY |
| NAME OF ISSUER | TITLE OF CLASS | CUSIP | FIGI | VALUE (x$1000) | SHRS OR PRN AMT | SH/PRN | PUT/CALL | INVESTMENT DISCRETION | OTHER MANAGER | SOLE | SHARED | NONE |
| 3M CO | COM | 88579Y101 |  | 1255717 | 8092 | SH |  | SOLE |  | 8092 | 0 | 0 |
| ABBOTT LABS | COM | 002824100 |  | 472942 | 3531 | SH |  | SOLE |  | 3531 | 0 | 0 |
| ABBVIE INC | COM | 00287Y109 |  | 2203618 | 9517 | SH |  | SOLE |  | 9517 | 0 | 0 |
| ACCENTURE PLC IRELAND | SHS CLASS A | G1151C101 |  | 612554 | 2484 | SH |  | SOLE |  | 2484 | 0 | 0 |
| ADOBE INC | COM | 00724F101 |  | 447993 | 1270 | SH |  | SOLE |  | 1270 | 0 | 0 |
| ADVANCED MICRO DEVICES INC | COM | 007903107 |  | 566103 | 3499 | SH |  | SOLE |  | 3499 | 0 | 0 |
| ALPHABET INC | CAP STK CL A | 02079K305 |  | 72892153 | 299844 | SH |  | SOLE |  | 299844 | 0 | 0 |
| ALPHABET INC | CAP STK CL C | 02079K107 |  | 4788520 | 19661 | SH |  | SOLE |  | 19661 | 0 | 0 |
| AMAZON COM INC | COM | 023135106 |  | 57732350 | 262934 | SH |  | SOLE |  | 262934 | 0 | 0 |
| AMPHENOL CORP NEW | CL A | 032095101 |  | 36792236 | 297311 | SH |  | SOLE |  | 297311 | 0 | 0 |
| ANALOG DEVICES INC | COM | 032654105 |  | 297297 | 1210 | SH |  | SOLE |  | 1210 | 0 | 0 |
| AON PLC | SHS CL A | G0403H108 |  | 223576 | 627 | SH |  | SOLE |  | 627 | 0 | 0 |
| APOLLO GLOBAL MGMT INC | COM | 03769M106 |  | 28928519 | 217067 | SH |  | SOLE |  | 217067 | 0 | 0 |
| APPLE INC | COM | 037833100 |  | 89455415 | 351315 | SH |  | SOLE |  | 351315 | 0 | 0 |
| ARISTA NETWORKS INC | COM SHS | 040413205 |  | 5082948 | 34884 | SH |  | SOLE |  | 34884 | 0 | 0 |
| ASML HOLDING N V | N Y REGISTRY SHS | N07059210 |  | 39143750 | 40434 | SH |  | SOLE |  | 40434 | 0 | 0 |
| AT INC | COM | 00206R102 |  | 396574 | 14043 | SH |  | SOLE |  | 14043 | 0 | 0 |
| AUTODESK INC | COM | 052769106 |  | 4470888 | 14074 | SH |  | SOLE |  | 14074 | 0 | 0 |
| AUTOMATIC DATA PROCESSING IN | COM | 053015103 |  | 727293 | 2478 | SH |  | SOLE |  | 2478 | 0 | 0 |
| BANK AMERICA CORP | COM | 060505104 |  | 646850 | 12538 | SH |  | SOLE |  | 12538 | 0 | 0 |
| BARCLAYS PLC | ADR | 06738E204 |  | 35035340 | 1694985 | SH |  | SOLE |  | 1694985 | 0 | 0 |
| BERKSHIRE HATHAWAY INC DEL | CL A | 084670108 |  | 3771000 | 5 | SH |  | SOLE |  | 5 | 0 | 0 |
| BERKSHIRE HATHAWAY INC DEL | CL B NEW | 084670702 |  | 6666835 | 13261 | SH |  | SOLE |  | 13261 | 0 | 0 |
| BOOKING HOLDINGS INC | COM | 09857L108 |  | 33254104 | 6159 | SH |  | SOLE |  | 6159 | 0 | 0 |
| BOSTON SCIENTIFIC CORP | COM | 101137107 |  | 629323 | 6446 | SH |  | SOLE |  | 6446 | 0 | 0 |
| BRISTOL-MYERS SQUIBB CO | COM | 110122108 |  | 663634 | 14715 | SH |  | SOLE |  | 14715 | 0 | 0 |
| BROADCOM INC | COM | 11135F101 |  | 68761668 | 208426 | SH |  | SOLE |  | 208426 | 0 | 0 |
| CAMECO CORP | COM | 13321L108 |  | 30557913 | 364392 | SH |  | SOLE |  | 364392 | 0 | 0 |
| CAPITAL ONE FINL CORP | COM | 14040H105 |  | 215981 | 1016 | SH |  | SOLE |  | 1016 | 0 | 0 |
| CATERPILLAR INC | COM | 149123101 |  | 1470099 | 3081 | SH |  | SOLE |  | 3081 | 0 | 0 |
| CHENIERE ENERGY INC | COM NEW | 16411R208 |  | 236860 | 1008 | SH |  | SOLE |  | 1008 | 0 | 0 |
| CHEVRON CORP NEW | COM | 166764100 |  | 2609091 | 16801 | SH |  | SOLE |  | 16801 | 0 | 0 |
| CISCO SYS INC | COM | 17275R102 |  | 716488 | 10472 | SH |  | SOLE |  | 10472 | 0 | 0 |
| CITIGROUP INC | COM NEW | 172967424 |  | 496741 | 4894 | SH |  | SOLE |  | 4894 | 0 | 0 |
| CLOROX CO DEL | COM | 189054109 |  | 1155074 | 9368 | SH |  | SOLE |  | 9368 | 0 | 0 |
| COCA COLA CO | COM | 191216100 |  | 238565 | 3597 | SH |  | SOLE |  | 3597 | 0 | 0 |
| COINBASE GLOBAL INC | COM CL A | 19260Q107 |  | 524122 | 1553 | SH |  | SOLE |  | 1553 | 0 | 0 |
| COLGATE PALMOLIVE CO | COM | 194162103 |  | 535518 | 6699 | SH |  | SOLE |  | 6699 | 0 | 0 |
| COMCAST CORP NEW | CL A | 20030N101 |  | 352627 | 11223 | SH |  | SOLE |  | 11223 | 0 | 0 |
| COSTCO WHSL CORP NEW | COM | 22160K105 |  | 58739461 | 63459 | SH |  | SOLE |  | 63459 | 0 | 0 |
| CROWDSTRIKE HLDGS INC | CL A | 22788C105 |  | 391323 | 798 | SH |  | SOLE |  | 798 | 0 | 0 |
| CURTISS WRIGHT CORP | COM | 231561101 |  | 482131 | 888 | SH |  | SOLE |  | 888 | 0 | 0 |
| DATADOG INC | CL A COM | 23804L103 |  | 201638 | 1416 | SH |  | SOLE |  | 1416 | 0 | 0 |
| DELTA AIR LINES INC DEL | COM NEW | 247361702 |  | 257929 | 4545 | SH |  | SOLE |  | 4545 | 0 | 0 |
| DRAFTKINGS INC NEW | COM CL A | 26142V105 |  | 243100 | 6500 | SH |  | SOLE |  | 6500 | 0 | 0 |
| EBAY INC. | COM | 278642103 |  | 325237 | 3576 | SH |  | SOLE |  | 3576 | 0 | 0 |
| ELI LILLY  CO | COM | 532457108 |  | 2045843 | 2681 | SH |  | SOLE |  | 2681 | 0 | 0 |
| EXXON MOBIL CORP | COM | 30231G102 |  | 2731373 | 24225 | SH |  | SOLE |  | 24225 | 0 | 0 |
| FAIR ISAAC CORP | COM | 303250104 |  | 12910564 | 8627 | SH |  | SOLE |  | 8627 | 0 | 0 |
| FORTINET INC | COM | 34959E109 |  | 352295 | 4190 | SH |  | SOLE |  | 4190 | 0 | 0 |
| GARTNER INC | COM | 366651107 |  | 565959 | 2153 | SH |  | SOLE |  | 2153 | 0 | 0 |
| GE VERNOVA INC | COM | 36828A101 |  | 29909351 | 48641 | SH |  | SOLE |  | 48641 | 0 | 0 |
| HIMS  HERS HEALTH INC | COM CL A | 433000106 |  | 351664 | 6200 | SH |  | SOLE |  | 6200 | 0 | 0 |
| HOME DEPOT INC | COM | 437076102 |  | 409647 | 1011 | SH |  | SOLE |  | 1011 | 0 | 0 |
| HSBC HLDGS PLC | SPON ADR NEW | 404280406 |  | 522271 | 7358 | SH |  | SOLE |  | 7358 | 0 | 0 |
| ICICI BANK LIMITED | ADR | 45104G104 |  | 31799360 | 1051914 | SH |  | SOLE |  | 1051914 | 0 | 0 |
| IDEXX LABS INC | COM | 45168D104 |  | 262584 | 411 | SH |  | SOLE |  | 411 | 0 | 0 |
| INTEL CORP | COM | 458140100 |  | 240084 | 7156 | SH |  | SOLE |  | 7156 | 0 | 0 |
| INTERNATIONAL BUSINESS MACHS | COM | 459200101 |  | 365397 | 1295 | SH |  | SOLE |  | 1295 | 0 | 0 |
| INTUIT | COM | 461202103 |  | 513469 | 752 | SH |  | SOLE |  | 752 | 0 | 0 |
| INVESCO QQQ TR | UNIT SER 1 | 46090E103 |  | 957882 | 1595 | SH |  | SOLE |  | 1595 | 0 | 0 |
| ISHARES BITCOIN TRUST ETF | SHS BEN INT | 46438F101 |  | 12404730 | 190842 | SH |  | SOLE |  | 190842 | 0 | 0 |
| ISHARES INC | MSCI WORLD ETF | 464286392 |  | 3035865 | 16721 | SH |  | SOLE |  | 16721 | 0 | 0 |
| ISHARES TR | CORE 1 5 YR USD | 46432F859 |  | 1036776 | 21228 | SH |  | SOLE |  | 21228 | 0 | 0 |
| ISHARES TR | CORE MSCI TOTAL | 46432F834 |  | 2740665 | 33188 | SH |  | SOLE |  | 33188 | 0 | 0 |
| ISHARES TR | CORE S ETF | 464287200 |  | 970485 | 1450 | SH |  | SOLE |  | 1450 | 0 | 0 |
| ISHARES TR | EXPND TEC SC ETF | 464287549 |  | 243335 | 1932 | SH |  | SOLE |  | 1932 | 0 | 0 |
| ISHARES TR | RUS 1000 GRW ETF | 464287614 |  | 358802 | 766 | SH |  | SOLE |  | 766 | 0 | 0 |
| ISHARES TR | ISHARES SEMICDTR | 464287523 |  | 209138 | 771 | SH |  | SOLE |  | 771 | 0 | 0 |
| ISHARES TR | CORE S TTL STK | 464287150 |  | 495938 | 3405 | SH |  | SOLE |  | 3405 | 0 | 0 |
| ISHARES TR | DOW JONES US ETF | 464287846 |  | 234943 | 1446 | SH |  | SOLE |  | 1446 | 0 | 0 |
| ISHARES TR | 10+ YR INVST GRD | 464289511 |  | 730064 | 14165 | SH |  | SOLE |  | 14165 | 0 | 0 |
| ISHARES TR | INTERNATIONAL SL | 46434V266 |  | 61481881 | 1495000 | SH |  | SOLE |  | 1495000 | 0 | 0 |
| JOHNSON  JOHNSON | COM | 478160104 |  | 2110972 | 11385 | SH |  | SOLE |  | 11385 | 0 | 0 |
| JPMORGAN CHASE  CO. | COM | 46625H100 |  | 70884301 | 224723 | SH |  | SOLE |  | 224723 | 0 | 0 |
| KLA CORP | COM NEW | 482480100 |  | 253471 | 235 | SH |  | SOLE |  | 235 | 0 | 0 |
| LINDE PLC | SHS | G54950103 |  | 34849858 | 73368 | SH |  | SOLE |  | 73368 | 0 | 0 |
| MASTERCARD INCORPORATED | CL A | 57636Q104 |  | 337873 | 594 | SH |  | SOLE |  | 594 | 0 | 0 |
| MCDONALDS CORP | COM | 580135101 |  | 5764336 | 18968 | SH |  | SOLE |  | 18968 | 0 | 0 |
| MCKESSON CORP | COM | 58155Q103 |  | 53222060 | 68892 | SH |  | SOLE |  | 68892 | 0 | 0 |
| MERCADOLIBRE INC | COM | 58733R102 |  | 37000771 | 15833 | SH |  | SOLE |  | 15833 | 0 | 0 |
| MERCK  CO INC | COM | 58933Y105 |  | 778031 | 9270 | SH |  | SOLE |  | 9270 | 0 | 0 |
| META PLATFORMS INC | CL A | 30303M102 |  | 65494158 | 89183 | SH |  | SOLE |  | 89183 | 0 | 0 |
| MICRON TECHNOLOGY INC | COM | 595112103 |  | 999904 | 5976 | SH |  | SOLE |  | 5976 | 0 | 0 |
| MICROSOFT CORP | COM | 594918104 |  | 87100777 | 168164 | SH |  | SOLE |  | 168164 | 0 | 0 |
| NETEASE INC | SPONSORED ADS | 64110W102 |  | 620879 | 4085 | SH |  | SOLE |  | 4085 | 0 | 0 |
| NETFLIX INC | COM | 64110L106 |  | 51460044 | 42922 | SH |  | SOLE |  | 42922 | 0 | 0 |
| NORFOLK SOUTHN CORP | COM | 655844108 |  | 354784 | 1181 | SH |  | SOLE |  | 1181 | 0 | 0 |
| NVIDIA CORPORATION | COM | 67066G104 |  | 112238688 | 601558 | SH |  | SOLE |  | 601558 | 0 | 0 |
| ORACLE CORP | COM | 68389X105 |  | 1078820 | 3836 | SH |  | SOLE |  | 3836 | 0 | 0 |
| PACIFIC BIOSCIENCES CALIF IN | COM | 69404D108 |  | 181888 | 142100 | SH |  | SOLE |  | 142100 | 0 | 0 |
| PALANTIR TECHNOLOGIES INC | CL A | 69608A108 |  | 83091033 | 455493 | SH |  | SOLE |  | 455493 | 0 | 0 |
| PALO ALTO NETWORKS INC | COM | 697435105 |  | 7015116 | 34452 | SH |  | SOLE |  | 34452 | 0 | 0 |
| PAYPAL HLDGS INC | COM | 70450Y103 |  | 258449 | 3854 | SH |  | SOLE |  | 3854 | 0 | 0 |
| PEPSICO INC | COM | 713448108 |  | 327096 | 2329 | SH |  | SOLE |  | 2329 | 0 | 0 |
| PROCTER AND GAMBLE CO | COM | 742718109 |  | 23469730 | 152748 | SH |  | SOLE |  | 152748 | 0 | 0 |
| ROBINHOOD MKTS INC | COM CL A | 770700102 |  | 77217690 | 539305 | SH |  | SOLE |  | 539305 | 0 | 0 |
| RTX CORPORATION | COM | 75513E101 |  | 930891 | 5563 | SH |  | SOLE |  | 5563 | 0 | 0 |
| SALESFORCE INC | COM | 79466L302 |  | 596766 | 2518 | SH |  | SOLE |  | 2518 | 0 | 0 |
| SCHWAB CHARLES CORP | COM | 808513105 |  | 3255374 | 34098 | SH |  | SOLE |  | 34098 | 0 | 0 |
| SCHWAB STRATEGIC TR | 5 10YR CORP BD | 808524698 |  | 790282 | 34241 | SH |  | SOLE |  | 34241 | 0 | 0 |
| SCHWAB STRATEGIC TR | FUNDAMENTAL US L | 808524771 |  | 224619 | 8541 | SH |  | SOLE |  | 8541 | 0 | 0 |
| SCHWAB STRATEGIC TR | INTL EQTY ETF | 808524805 |  | 223628 | 9606 | SH |  | SOLE |  | 9606 | 0 | 0 |
| SCHWAB STRATEGIC TR | US LRG CAP ETF | 808524201 |  | 382740 | 14531 | SH |  | SOLE |  | 14531 | 0 | 0 |
| SHOPIFY INC | CL A SUB VTG SHS | 82509L107 |  | 388764 | 2616 | SH |  | SOLE |  | 2616 | 0 | 0 |
| SMUCKER J M CO | COM NEW | 832696405 |  | 386182 | 3556 | SH |  | SOLE |  | 3556 | 0 | 0 |
| SPDR DOW JONES INDL AVERAGE | UT SER 1 | 78467X109 |  | 296794 | 640 | SH |  | SOLE |  | 640 | 0 | 0 |
| SPDR GOLD TR | GOLD SHS | 78463V107 |  | 244919 | 689 | SH |  | SOLE |  | 689 | 0 | 0 |
| SPDR S 500 ETF TR | TR UNIT | 78462F103 |  | 1768343 | 2654 | SH |  | SOLE |  | 2654 | 0 | 0 |
| SPOTIFY TECHNOLOGY S A | SHS | L8681T102 |  | 35194556 | 50422 | SH |  | SOLE |  | 50422 | 0 | 0 |
| STRYKER CORPORATION | COM | 863667101 |  | 662079 | 1791 | SH |  | SOLE |  | 1791 | 0 | 0 |
| SYSCO CORP | COM | 871829107 |  | 203792 | 2475 | SH |  | SOLE |  | 2475 | 0 | 0 |
| T-MOBILE US INC | COM | 872590104 |  | 43165136 | 180321 | SH |  | SOLE |  | 180321 | 0 | 0 |
| TAIWAN SEMICONDUCTOR MFG LTD | SPONSORED ADS | 874039100 |  | 61687062 | 220871 | SH |  | SOLE |  | 220871 | 0 | 0 |
| TELEDYNE TECHNOLOGIES INC | COM | 879360105 |  | 212146 | 362 | SH |  | SOLE |  | 362 | 0 | 0 |
| TESLA INC | COM | 88160R101 |  | 5790466 | 13020 | SH |  | SOLE |  | 13020 | 0 | 0 |
| TEXAS INSTRS INC | COM | 882508104 |  | 294887 | 1605 | SH |  | SOLE |  | 1605 | 0 | 0 |
| THERMO FISHER SCIENTIFIC INC | COM | 883556102 |  | 483080 | 996 | SH |  | SOLE |  | 996 | 0 | 0 |
| TMC THE METALS COMPANY INC | COM | 87261Y106 |  | 63700 | 10000 | SH |  | SOLE |  | 10000 | 0 | 0 |
| TRANE TECHNOLOGIES PLC | SHS | G8994E103 |  | 33170276 | 78610 | SH |  | SOLE |  | 78610 | 0 | 0 |
| TRIMBLE INC | COM | 896239100 |  | 317047 | 3883 | SH |  | SOLE |  | 3883 | 0 | 0 |
| UBER TECHNOLOGIES INC | COM | 90353T100 |  | 44362775 | 452820 | SH |  | SOLE |  | 452820 | 0 | 0 |
| VANGUARD INDEX FDS | S 500 ETF SHS | 922908363 |  | 647230 | 1057 | SH |  | SOLE |  | 1057 | 0 | 0 |
| VANGUARD INDEX FDS | TOTAL STK MKT | 922908769 |  | 542137 | 1652 | SH |  | SOLE |  | 1652 | 0 | 0 |
| VISA INC | COM CL A | 92826C839 |  | 60456135 | 177093 | SH |  | SOLE |  | 177093 | 0 | 0 |
| WALMART INC | COM | 931142103 |  | 35131639 | 340885 | SH |  | SOLE |  | 340885 | 0 | 0 |
| WELLS FARGO CO NEW | COM | 949746101 |  | 3108465 | 37085 | SH |  | SOLE |  | 37085 | 0 | 0 |
| WORLD GOLD TR | SPDR GLD MINIS | 98149E303 |  | 35691753 | 466864 | SH |  | SOLE |  | 466864 | 0 | 0 |
| XYLEM INC | COM | 98419M100 |  | 488668 | 3313 | SH |  | SOLE |  | 3313 | 0 | 0 |

---