Uncertainty around the U.K.'s referendum on its EU membership and a possible rate hike from the U.S. Federal Reserve has left investors cautiously looking ahead towards the month of June.
Stocks entered the final trading day of May with solid gains across the U.S. and Europe for the month, supported by a 5 percent jump in the oil price. But analysts have warned that June is the worst month of the year for markets.
"Eight of the last ten Junes has been down," Michael Browne, fund manager at Martin Currie told CNBC.
"It is the worst month of the year in the last decade, not by a little bit but by an absolute street. If you were just going to use that as a way of looking forward and that's what you should do, just bet on a negative June, sell on the last day of May. It has worked at least eight out of the last ten times."
Browne explained that the bottoming out of earnings in 2016 had occurred at an early stage of the year, which was very unusual. He added that earnings had ended pretty much flat in Europe for the last eight to nine years. However, he added that if the trend continued in 2016 then we may see a better June.
"Year-to-date over the last six months we have seen markets move really closely around corporate earnings. So November, December people realize that corporate earnings estimates are way above any reality that comes through."
Some analysts have also pointed to rising commodity prices as reasons for global stocks to have made gains in May. Oil has been on the rise in recent weeks due to a number of supply outages helping it flirt with $50 a barrel.
However, investors have been cautious ever since Federl Reserve chair Janet Yellen said last week that an interest rate hike is "probably" appropriate in the coming months if economic data improve.
"It's appropriate, and I've said this in the past, I think for the Fed to gradually and cautiously increase our overnight interest rate over time and probably in the coming months, such a move would be appropriate," she said in response to a question at Harvard's Radcliffe Institute for Advanced Study on Friday.
Those betting on a June rate hike are eagerly going to watch another speech on June 6 by Yellen, post payrolls data which are due on Friday.