** Cannabis producer’s U.S.-listed shares fall 4.4 pct to $19.34 in premarket after two brokerages downgrade stock
** Canaccord Genuity downgrades to “sell” from “hold” citing valuation concerns
** CRON has nearly doubled in value since Marlboro cigarette maker Altria Group made $1.8 bln investment on Dec. 7
** CRON’s last close was C$27.06 vs investment price of C$16.25, which brokerage calls a stretch
** Co posted disappointing results on Monday, which Canaccord said was in a period that represented CRON’s first full quarter of recreational sales in Canada
** PI Financial cuts to “neutral” from “buy”
** With ~28,000 shares traded at 6:15 a.m. ET, CRON is the 2nd most heavily traded U.S. stock (Reporting by Amy Caren Daniel in Bengaluru)