Buyback shares may not be being bought on the open market. They could be getting shares from some of those that could not sell, even at $0.0001, when HRNF was at no bid in 2010.
These could be insiders, the Chinese manufacturer, paid stock promoters, or even management who may have been paid in shares. We all know the CEO is owed a LOT of money from loans he made to the company, plus deferred compensation. The money owed represents a huge percentage of the current market cap.
They could even be using money from sales of shares to buyback some of these shares. Since HRNF provides little disclosure and does not file audited financials, one may never know.
