Just curious what your experience level is in the stock market?
Have you ever seen an FDA approval in a biotech stock? The PPS is based on the willingness of buyers and sellers to buy/sell at a particular price at that given moment not just the amount of buyers and sellers. If Hoghset was willing to sell at lower prices than Garrett was willing to buy, then the price would still go down even as Garrett accumulated. No doubt Garrett also picked up the share difference from exhausted retail investors as well.