Stephen Guilfoyle, a 30-year Wall Street veteran who now runs Sarge986 LLC, a family trading operation, attributed Palantir’s recent decline to profit-taking by short-term traders. He noted that the “swing crowd” likely locked in gains as the stock tested a key moving average, accelerating the sell-off.

NEW YORK — Wall Street faded on Tuesday following drops for Nvidia and other stars that have been riding the mania surrounding artificial-intelligence technology. The S&P 500 fell 0.6% for a third straight loss The heaviest weight on the market was Nvidia,