The recent strength in the euro, as well as rises in other global markets, bear a worrying similarity to the bubble-like conditions seen before the global financial crash of 2008, according to Simon Derrick, chief currency strategist at BNY Mellon.
"A lot of the price action that we have seen over the last 20 months is a real echo of what we saw between late 2005 and the summer of 2007," he told CNBC Wednesday.
In the last 20 months, four key metrics have aligned to show surprising correlation with levels seen in the pre-financial crisis period, Derrick said. The euro has risen from $1.21 to $1.37, the German DAX has rallied by 46 percent and the difference between the one-year deposit rate on the euro and the dollar has narrowed.
His comments come amid a global stock market rally, which saw the S&P 500 clock up its seventh record close this year on Tuesday. In Europe, London's FTSE 100 closed at a three-week high on Wednesday and the FTSEurofirst 300 Index closed higher for a seventh-straight day.
Meanwhile, emerging markets – which faced something of a battering at the start of the year – have found renewed strength. The MSCI Emerging Markets Index is up around 7 percent since February.
As a result, the worldwide benchmark FTSE All-World index rose 0.17 percent to hit its highest level since December 2007 on Wednesday - and this global rally has some way to go, according to Andrew Goldberg, global market strategist at J. P. Morgan Asset Management.
"This cycle is going to go well beyond fair value, and there's a number of reasons for it. Monetary value is still very easy. You've got very little competition in the form of fixed income, in terms of what those rates are offering," Goldberg told CNBC.
"This market has plenty of room to run. This could go on two or three more years."