** Shares of software company MongoDB MDB.O down 15.8% to $222.50 in extended trade
** MDB forecasts FY26 revenue and adjusted EPS below Wall Street expectations
** Dour forecast overshadows Q4 results beat
** Company says forecast assumes non-Atlas revenue will decline in high-single digits
** Atlas service helps clients manage their databases on the cloud
** As of last close, MDB stock up 13.5% YTD