Guarseed prices extended losses by R1,140 to R27,570 per quintal in futures trading today, owing to all-round selling by traders. Marketmen said speculators booked profit after the exchange authority imposed ban on creating fresh positions till September. At the National Commodity and Derivatives Exchange, guarseed prices for April contract slid by R1,140, 3.97%, to R27,570 per quintal.