Under share buyback rules, they are limited by the market...

Under share buyback rules, they are limited by the market volumes and the VWAP. They cannot simply decide to purchase 500K in a day. Unless there is the market volumes to support this. I do not know what the actual limits are but I suspect that a company cannot be more than 25% of the volume on a given day. For a more extreme example, check out WOTSO, sometimes trades <100 shares a day, and the buyback can be 10 shares

I would think the buyback would stay in place until 80c or so... which might be years away anyway.