Notably, it was AI-connected companies that climbed at the beginning of Tuesday's trading - but then the AI sky darkened.
At the close, the Dow Jones Industrial Average had risen 0.2 percent, while the broad S&P 500 index was down 0.3 percent and the tech-heavy Nasdaq Composite was down 1 percent.
As oil prices fell and no clear negative signs emerged, commentators searched for an explanation. They landed on: profit-taking in the technology sector.
After Monday's rise following Friday's decline, chip companies Marvell Technology and Qualcomm had another tough day, down 7.6 and 5.7 percent respectively.
Intel, AMD, Micron Technology and Broadcom, among others, also fell sharply.
