The lifeline that Warren Buffett just handed Shigeru Ishiba couldn’t come at a better moment for the beleaguered Japanese prime minister.

In a nutshell, buying Berkshire Hathaway is nearly akin to buying a broad market index fund, except there's no expense ratio and the underlying holdings are curated by a legendary investor and his handpicked team. If you're considering putting money into an index fund, consider instead simply buying some Berkshire stock.