AUM
Not disclosed
Principals
4
Principal Net Worth
$7.0B
Data Flags
Wealth through The Washington Companies conglomerate; Forbes 400 #181 2025; Montana's richest person; significant philanthropy ($500M+ donated); Horatio Alger Award 1995
Washington Family Office
SFOHigh ConfidenceMissoula, Montana, USA
Last verified: Jan 16, 2026
Details
- Source of Wealth
- Construction, Mining, Rail, Marine
- Assets Under Management
- Not disclosed
- Source File
- research/organizations/washington-family-office.md
- UID
- fo-washington-family-office
Also Known As
Dennis Washington Family OfficeWashington CapitalWashington Companies Family Office
Principals (4)
Team Members (1)
Related Entities (6)
Aviation Partners Inc.Subsidiary
Aviation technology
Dennis and Phyllis Washington FoundationFoundation
Philanthropy
Montana Rail LinkSubsidiary
Regional railroad
Montana Resources LLPSubsidiary
Mining operations
Seaspan ULC/Seaspan CorporationSubsidiary
Marine transportation and shipbuilding
The Washington CompaniesSubsidiary
Holding company for all businesses
Relationship Strength
Loading relationships...
Sources (4)
Changelog
- 2026-01-16Upgraded to High confidence - Forbes 400 #181 confirms $7B; Wikipedia confirms; Montana's richest person verified across multiple sources; $500M+ philanthropy confirmed
- 2026-01-16Enriched with biography (born July 27 1934 Spokane), career building Washington Companies, holdings list, family details including son Kyle (Seaspan), awards; updated net worth to $7.0B+; confidence updated to Medium
- 2026-01-15Auto-generated from principal Dennis Washington