** Shares in Geberit GEBN.S fall 4% after the Swiss plumbing supplier reports Q2 results miss
** Geberit's second-quarter EBITDA reached 236.9 million Swiss francs ($293.19 million), while net sales totalled 786.5 million Swiss francs, both coming in about 2% below analysts' expectations
** "Key KPI's below Street expectations," Vontobel says
** The stock is among the worst performers on STOXX 600 index .STOXX, dropping to its lowest in 85 days
($1 = 0.8080 Swiss francs)
(Reporting by Anastasiia Kozlova)
((Anastasiia.Kozlova@thomsonreuters.com))