Berkshire has a lot of the characteristics of an index fund being a diversified conglomerate (admittedly over weight financials / insurance) and with the added tax advantage of being averse to paying a dividend.....instead depoyling cash on new businesses or buying back it's own shares.
You also get two of the best capital allocaters in the biz working for you.
You also get two of the best capital allocaters in the biz working for you.