My guess the SP slide is not unrelated to the recent exercise of options at lower prices.
With the current lack of interest in BAR due to not much happening - it does not take much for the price to dip significantly if someone wants to cash in their holdings. The shares have to be paid fore when the option is exercised - even if it is cheap. If someone is keen to sell some sort of volume when the only buyers are savvy accumulators, the SP will tank.