MAD RIVER INVESTORS — 13F Holdings & Portfolio
CIK 1384484 · latest 13F-HR filed 2026-08-03
MAD RIVER INVESTORS manages $268.1M in 13F-reported U.S. long-equity assets across 30 reported positions as of its 2026-06-30 13F-HR filing. Its largest disclosed positions are TPL (46.58%), PBT (9.39%), LB (7.92%). Quarter over quarter (versus its 2026-03-31 filing) the fund opened 2 new positions, exited 4, added to 11, and trimmed 13.
AUM is the long-equity portion reported on Form 13F-HR. Excludes short positions, cash, foreign holdings, and non-13F assets. For informational purposes only — not investment advice.
SUITE 1060
BOSTON, MA 02109
$268.1M
Long-equity book
30
Distinct positions
2026-06-30
Filed 2026-08-03
+2 / −4 / ↑11 / ↓13
vs 2026-03-31
| Name | Title / Status | Ownership | Type |
|---|
Top Adds (vs prior quarter)
- MIAMI INTL HLDGS INC$7.6M +239.6%
- PERMIAN BASIN RTY TR$3.6M +16.6%
- LANDBRIDGE COMPANY LLC$2.8M +15.4%
- WATERBRIDGE INFRASTRUCTURE L$1.9M +26.5%
- PALO ALTO NETWORKS INC$991.0K +112.7%
Top Trims
- TEXAS PACIFIC LAND CORPORATI-$10.4M -7.7%
- WHEATON PRECIOUS METALS CORP-$5.4M -46.1%
- GRAYSCALE BITCOIN TRUST ETF-$2.6M -13.7%
- MESABI TR-$1.9M -19.1%
- HAWAIIAN ELEC INDS INC MTN B-$1.7M -8.5%
Exited Positions
- CARNIVAL CORP$4.0M
- ROYAL GOLD INC$626.8K
- JPMORGAN CHASE & CO$416.8K
- VANGUARD SPECIALIZED FUNDS$215.1K
Rows tagged Call or Put are options positions, not stock. Per SEC Form 13F-HR, Value shows the notional value of the underlying (shares covered × underlying price), not the option premium. Shares is the number of underlying shares covered (divide by 100 for contract count).
| # | Issuer | Symbol | CUSIP | Value | Weight | Shares | Type |
|---|---|---|---|---|---|---|---|
| 1 | TEXAS PACIFIC LAND CORPORATI | TPL | 88262P102 | $124.9M | 46.58% | 285,330 | SH |
| 2 | PERMIAN BASIN RTY TR | PBT | 714236106 | $25.2M | 9.39% | 1,005,152 | SH |
| 3 | LANDBRIDGE COMPANY LLC | LB | 514952100 | $21.2M | 7.92% | 267,953 | SH |
| 4 | HAWAIIAN ELEC INDS INC MTN B | HE | 419870100 | $17.9M | 6.67% | 1,321,850 | SH |
| 5 | GRAYSCALE BITCOIN TRUST ETF | GBTC | 389637109 | $16.4M | 6.11% | 360,139 | SH |
| 6 | MIAMI INTL HLDGS INC | MIAX | 59356Q108 | $10.7M | 4.01% | 289,000 | SH |
| 7 | WATERBRIDGE INFRASTRUCTURE L | WBI | 940923105 | $9.2M | 3.42% | 267,801 | SH |
| 8 | MESABI TR | MSB | 590672101 | $8.2M | 3.05% | 323,735 | SH |
| 9 | WHEATON PRECIOUS METALS CORP | WPM | 962879102 | $6.3M | 2.35% | 56,173 | SH |
| 10 | FRANCO NEV CORP | FNV | 351858105 | $4.7M | 1.75% | 22,506 | SH |
| 11 | FIDELITY WISE ORIGIN BITCOIN | FBTC | 315948109 | $3.6M | 1.34% | 70,369 | SH |
| 12 | CARNIVAL CORP LTD | CCL | G2004J103 | $2.7M | 1.02% | 95,373 | SH |
| 13 | VANGUARD INDEX FDS | VTI | 922908769 | $2.5M | 0.94% | 6,800 | SH |
| 14 | GRAYSCALE BITCOIN MINI TR ET | BTC | 389930207 | $2.1M | 0.79% | 81,517 | SH |
| 15 | PALO ALTO NETWORKS INC | PANW | 697435105 | $1.9M | 0.70% | 5,484 | SH |
| 16 | CBOE GLOBAL MKTS INC | CBOE | 12503M108 | $1.6M | 0.61% | 6,705 | SH |
| 17 | APPLE INC | AAPL | 037833100 | $1.5M | 0.55% | 5,050 | SH |
| 18 | ORACLE CORP | ORCL | 68389X105 | $1.2M | 0.44% | 8,050 | SH |
| 19 | INTERCONTINENTAL EXCHANGE IN | ICE | 45866F104 | $965.9K | 0.36% | 7,846 | SH |
| 20 | AMAZON COM INC | AMZN | 023135106 | $810.4K | 0.30% | 3,400 | SH |
| 21 | UNITEDHEALTH GROUP INC | UNH | 91324P102 | $706.6K | 0.26% | 1,700 | SH |
| 22 | CISCO SYS INC | CSCO | 17275R102 | $704.8K | 0.26% | 6,000 | SH |
| 23 | CINCINNATI FINL CORP | CINF | 172062101 | $666.5K | 0.25% | 3,600 | SH |
| 24 | HAWAIIAN ELEC INDS INC MTN B Call | HE | 419870100 | $660.3K | 0.25% | 48,800 | PRN |
| 25 | EATON CORP PLC | ETN | G29183103 | $511.3K | 0.19% | 1,200 | SH |
| 26 | RLI CORP | RLI | 749607107 | $354.4K | 0.13% | 6,000 | SH |
| 27 | BERKSHIRE HATHAWAY INC DEL | BRK.B | 084670702 | $312.7K | 0.12% | 625 | SH |
| 28 | JOHNSON & JOHNSON | JNJ | 478160104 | $304.8K | 0.11% | 1,200 | SH |
| 29 | CACI INTL INC | CACI | 127190304 | $210.8K | 0.08% | 455 | SH |
| 30 | FERMI INC | FRMI | 314911108 | $151.1K | 0.06% | 16,500 | SH |
| Period | Filed | AUM | Holdings | Accession |
|---|---|---|---|---|
| 2026-06-30 | 2026-08-03 | $268.1M | 30 | 0001384484-26-000006 |
| 2026-03-31 | 2026-04-23 | $277.9M | 32 | 0001384484-26-000004 |
| 2025-12-31 | 2026-02-06 | $219.6M | 35 | 0001384484-26-000002 |