Starbucks isn’t just the world’s largest coffee chain; it’s a bellwether stock, one that tells us a disproportionate amount about the American economy and where it may be headed.

When Barack Obama was president of the US, he used to call Starbucks founder and former chief executive, Howard Schultz, for a read on the American consumer. The store sales figures coming out of thousands of communities around the country, four times a day, were much more sensitive than any Bureau of Labor Statistics data.

Last week, Starbucks told us something important and disturbing. The company’s stock took a dive after it signalled, during a presentation at a Goldman Sachs retail conference, that its recent 10 per cent rate of profit expansion wouldn’t carry into next year. In large part, this was because the benefits from President Donald Trump’s tax cuts were tapped out.