Nvidia (NVDA) was the number one sold stock by Charles Schwab's clients, according to Joe Mazzola. Meanwhile, UnitedHealth (UNH) was the second-most bought stock even though the company slipped 50% in the span of weeks. Joe attributes the strange trend to a rotation out of tech to a "month of dip buying in unloved names." He notes lasting uneasiness, with Joe suggesting clients are moving from a bearish tone to a neutral one.