Value is in the eye of the beholder, even when valuing value investors. Warren Buffett's Berkshire Hathaway can now be had for 1.18 times book value, which – depending on how one looks at it – is cheap or expensive.

Closed-end funds typically trade at a discount to book of 5 to 15 per cent. Even well-run conglomerates sell at a discount to break-up value. Loews, with similar holdings to Berkshire, is at a 10 per cent discount.

But Berkshire is, of course, no ordinary conglomerate, so a mere 18 per cent premium to book is among the cheapest entry-points in decades. Over the past 18 years investors have paid 1.7 times book on average. Anyone who balked at paying 1.3 times in 1991, as the US was exiting a recession, missed out on a tenfold return. Since 1964, Berkshire's book value has grown more than 400,000 per cent versus 5,000 per cent for US stocks overall.