Jeremy Grantham, the co-founder US asset manager GMO, has echoed the calls of other high-profile investors with a bullish assessment of the equity markets and has forecast the asset class is likely to build on the rally which began to develop a head of steam in March.

In his latest strategy note, Grantham wrote: "We are likely to have a remarkable stock rally, far in excess of anything justified by either long-term or short-term economic fundamentals.