If there were a prevalence of buyers the sp would go up if they were willing to buy at higher price. Actually there is no prevalence of buyers or sellers, just Offers to sell or buy. There is no trade where there is only one without the other. The difference is in one or the other willing to trade at higher or lower price. By sell pressure I mean that some of those sellers were willing to sell at lower price just to get out. They chased the buyers into ever lower sp and that is what lowered the price.