Berkshire Hathaway’s 6% stake in Apple (245 million shares as of March 31) is currently valued at $100 billion, or 21% of Berkshire’s market capitalization of $472 billion.
Berkshire Hathaway’s stake in Apple ($100 billion), plus its cash as of March 31 ($137 billion), plus its stock portfolio less Apple as of March 31 ($113 billion) equal $350 billion or 74% of its market capitalization of $472 billion. Therefore, all of its businesses are being valued at only $122 billion.
Since Berkshire’s stock portfolio has very likely appreciated since March 31, which was close to the market bottom, then all of its businesses are being valued at less than $122 billion. Berkshire’s 60+ businesses include BNSF railroad, Berkshire Hathaway Energy, its insurance operations (Geico, etc.), and its manufacturing companies.