Even as the European Central Bank (ECB) halts stimulus, it looks as if the economy needs revving up again.
In December the bank said it would stop expanding its 2.6trn euro ($3trn) bond-buying scheme.
But on the same day it trimmed its forecasts of economic growth and warned that "the balance of risks is moving to the downside".
Its warnings have now materialised. Several measures of economic activity in the euro zone have disappointed in recent weeks.
The much-touted "euroboom" that began in 2017 has run its course.
The slowdown was first thought to be temporary.
At the start of 2018 sluggish growth in Germany, the bloc's largest economy,
was blamed on one-off factors ranging from an outbreak of flu to labour disputes and the timing of national holidays.
Weak third-quarter data was chalked up to bottlenecks in the car industry, which had to meet new emissions standards for diesel engines.
In the fourth quarter the populist gilets jaunes protests in France dealt growth another temporary blow.
The demonstrations are expected to have lowered output in the euro zone's second-largest economy by 0.1%.
But recent figures suggest the economic slowdown is broad-based.
"There is more going on than the one-offs that have continually plagued the euro-zone economy," says Bert Colijn, an economist at ING, a bank.
"It's not country- or sector-specific anymore. The weakness is widespread," says Felix Huefner of UBS, another bank.
On January 4th IHS Markit, a data provider, said that in December its euro-zone purchasing managers' index (PMI)
—a closely watched gauge of economic activity—fell to a four-year low.
PMIS declined in the zone's four largest economies, Germany, France, Italy and Spain.
Figures released on January 14th revealed that euro-zone industrial production fell by 3.3% year-on-year in November.
That is its largest annual decline in six years.