A stock market crash is a way off, but this boom will turn to bust | Larry Elliott

Markets are at record highs, but optimism breeds recklessness. The question is how big the bubble will get before it bursts

All three main measures of the health in the stock market are at record levels. Donald Trump is bragging about the boost he has given to share prices. Bourses around the world are taking their lead from Wall Street and heading higher.

What does that mean? It means the stock market is going to crash because sooner or later optimism breeds recklessness and boom will turn to bust. All that's in question is how big the bubble will get before it bursts and when that moment will come.

Stock market hits new high with longest winning streak in decades. Great level of confidence and optimism - even before tax plan rollout!

Related: World stock markets hit record highs - business live