"It’s been 20 years or so since Alan Greenspan made his famous ‘irrational exuberance’ speech and today’s stock market is displaying many of the signs of running ahead of itself. Bears will say that after a multi-year bull market for equities, this could just be the final crazy push higher before it all unravels. However, bull markets normally only turn into bear markets on an expected downturn in the real economy. There is little evidence that the US is heading for recession – quite the reverse as Trump is ushering a new era of pro-business policies that affirm growth prospects.

"We are seeing a massive shift in investor sentiment that has seen money pour out of bonds and into equities around the world. This is a major recalibration in global stocks and bond markets – ie, not a bubble in the pure sense, although it might be rising faster than is natural.

"A bubble, as Greenspan noted, is very hard to stop once it starts. And while his words cooled the market briefly, it quickly turned positive again and continued to rise and rise in the years after. Investors have to judge whether the real returns from equities are worth the prices asked. At the current velocity there is a chance that this calculation could change and we could see a correction, but if this is a real rotation from bonds into stocks, ending a 30-year bond bull market, there is still a huge amount of cash piled up that could yet pour into equities and power further gains through 2017. It might not be too long before 21,000 is in sight.”