Starbucks shares plunged as much as $2.10 in after-hours trading despite releasing record full year results.
Starbucks' revenue for the last quarter (the three months to 27 September) was $4.91bn (£3.2bn), in line with forecasts. The 18 per cent increase from $4.18bn last year is a record for the company.
Fourth quarter operating profits were also at a record high, at $969m.
Earnings per share were up to a record $0.43 from $0.37, exactly on analysts' target.
Dividends increased 25 per cent to $0.20 a share.
Full year operating profit and revenues rose by 17 per cent - to $3.6bn and a record $19.2bn respectively.
Starbucks said it served 72 million more customers globally this year, with worldwide sales for 2015 up seven per cent.
Why it's interesting
Shares fell as much five per cent as investors were left disappointed by the company's muted forecasts for the first quarter of 2016.
The company said it expected earnings per share to remain in the $0.43-$0.44 range for the first three months of 2016.
It also predicted margins would remain flat, or even decrease, in China and Asia, where it has plans to open another 900 stores, and this year saw a nine per cent rise in sales, driven by an eight per cent increase in traffic.
There was only moderate growth in the US.
Last week the EU ruled Starbucks would have to pay back up to €30m in "illegal" tax breaks it had received in the Netherlands, which is not the first time the company has attracted criticism over its tax arrangements.
What Starbucks said
Howard Schultz, Starbucks chairman and chief executive, said: “Starbucks' record fourth quarter financial results, highlighted by stunning store sales increases of eight per cent globally, nine per cent in the US driven by a four per cent increase in global traffic, demonstrate the strength and relevance of the Starbucks brand around the world.
"And our results underscore the success of the investments we continue to make in our people and business, in new beverage and food innovation and in groundbreaking technology innovation that is deepening our connection to customers everywhere."
Chief financial officer Scott Maw said:"Our fourth quarter results are particularly gratifying in that they were achieved despite the increase, and acceleration, of the significant partner and digital investments we are making to drive sustained, profitable growth around the world and into the future."
2015's record revenues are only good news if the company can keep building on that, which investors seemed to doubt this evening.