Compass Minerals falls after J.P.Morgan double downgrades to 'underweight'

** Shares of Compass Minerals International CMP.N down 2.1% at $18.8 premarket

** J.P.Morgan double downgrades commodity chemicals firm to "underweight" from "overweight"

** JPM favors larger agricultural companies like Nutrien and Mosaic on stronger finances, potential tariff benefits

** Raises PT to $18 from $15, representing a marginal downside to the stock's last close

** Compass Minerals Q3 revenue met analysts' estimates

** 1 of 3 brokerages rate the stock "buy," 1 "hold" and 1 "sell;" their median PT is $20 - data compiled by LSEG

** As of last close, CMP up 70.8% YTD