Shares of Compass Minerals International (CMP) plummeted 5.05% in Wednesday's pre-market trading session following a double downgrade by J.P. Morgan. The investment bank cut its rating on the commodity chemicals firm to "underweight" from "overweight", triggering a significant sell-off in the stock.

Despite the downgrade, J.P. Morgan raised its price target for Compass Minerals to $18 from $15. However, this new target still represents a slight downside from the stock's previous closing price. The move by J.P. Morgan reflects a preference for larger agricultural companies like Nutrien and Mosaic, citing their stronger finances and potential tariff benefits.

The downgrade comes at a time when Compass Minerals had been performing well year-to-date, with the stock up 70.8% before this setback. The company's recent third-quarter revenue met analysts' estimates, but it wasn't enough to prevent the negative outlook from J.P. Morgan. Currently, out of three brokerages covering the stock, one rates it as "buy," one as "hold," and one as "sell," with a median price target of $20.