2021 is turning out to be some year for stocks. The S&P 500 has closed at record highs on over a quarter of all trading days this year, according to Bespoke Investment. If the current pace of new highs continues, 2021 would trail only two years (1995 and 1964) for the most new highs.

New highs aside, stocks have gained 13 per cent and the worst peak-to-trough drawdown has been just 4.2 per cent.

Things have been even better outside the US. The percentage of developed countries at 52-week highs has comfortably exceeded the percentage of US industries at new highs, notes SentimenTrader's Jason Goepfert, with almost 40 per cent of countries hitting new 52-week highs recently.

It's been "too easy", says Ritholtz Wealth Management's Ben Carlson, although global investors are due some good fortune. The MSCI World ex-USA Index's recent all-time high was its first in 14 years – a record drought since its inception in 1969.