Krispy Kreme Inc. has joined Opendoor Technologies Inc. and Kohl's Corp. in the latest meme-stock wave as shares of the doughnut maker skyrocket amid a wild week for the names.

He also charted S&P 500 performance after 60 days above the 20-day moving average, which has happened eight times before, but now for the first time in the 21st century. There was one instance, in ...