Although typically the old adage "sell in May and go away" until the U.K.'s St Leger horseracing festival in mid-September, those opting at the start of the month to stay on the sidelines will be kicking themselves.
May is traditionally dire in many stock-pickers' handbooks, but equities have enjoyed a modest rally as it closes out the month on Friday. The S&P 500, which hit another all-time high Thursday, is set to end May with a gain of around 2 percent, its best month since February. Similar rallies have been seen on Japan's Nikkei 225 - which saw its first gain for five months - and the pan-European Euro Stoxx 600 Index.
Top of the heap includes Russia's Micex index, bouncing back 10 percent in May as investors grew increasingly confident in the country's stocks despite the Ukraine crisis. Germany's DAX index has also hit an all-time high and has logged a gain of 3.5 percent.
"The 'sell in May' call has not worked in its first month in 2014, with many global indices at or near their recent highs," Peel Hunt equity strategist Ian Williams said in a research note on Friday.