The long-feared threat of euro area deflation finally materialized at the end of 2014, data showed on Wednesday.
Consumer prices across the euro zone fell by 0.2 percent year-on-year in December, according to this first official estimate—worse than the 0.1 percent decline forecast, and down from November's 0.3 percent rise.
Markets took the news on the chin however, with stock indexes in most euro zone countries, bar Greece, continuing to gain.
So does deflation in Europe's 19-country currency union really matter? CNBC takes a look at why central bankers, economists and politicians have reason to be worried.