Trump is happy to risk a severe market reaction, but what will he do when his tariffs backfire?

So much for the idea that "liberation day" would free financial markets from their fear of the unknown.

- Nils Pratley

Publication of precise tariff rates, went a cheerful line of advance thinking, would at least allow investors to assess the probable trade effects on the basis of hard information. True optimists clung to the idea that Donald Trump would not risk a truly severe market reaction.

That was blown apart when the president reached for his pub-style display of wares. This was a return to the tariff rates of the 1920s or 1930s on all US goods imports. The S&P 500 index fell 4% in early trading and is down more than 10% from its high six weeks ago. The dollar fell sharply, even though traditional logic says tariffs ought to be currency-positive if $600bn (£460bn) of extra revenue is on the cards. The market just adjusted to the higher likelihood of a US recession from higher prices and slower growth.

Instead of clarity, there are more questions. The first is a common one with Trump announcements: how much is designed to be permanent, and how much is theatre to provoke a negotiation?