Yes to the first, no to the second. They are a different breed of cat altogether from the longs here; we are banking on the success of the molecule and the company, they are % ROI people. Accordingly they will exercise and sell at price points which may seem irrational to us, and can be responsible for some of the shorting we see as well; warrant holders can and do "short against the warrant". They do this by shorting the requisite number of shares first, then exercising and delivering the shares to their broker. This locks in their profit at a set number and exerts no upward pressure on the share price, since they're using newly-issued shares to cover.