'Full-blown mania': US stock market jackpot bells just keep ringing

Four days after ending the year at almost 40x earnings, the Nasdaq 100 Index posted its biggest rally in two months

Like a slot machine paying off on every pull, the stock market’s most reliable bets lately have often been its riskiest.

Go long a company that sounds like something Elon Musk mentioned in a tweet (but wasn’t)? Signal Advance just soared 12-fold. Lend money to a software maker to buy Bitcoin? A Microstrategy convertible bond is up 50 per cent in four weeks (its option is in the money).

Throw a dart, hit a winner, so it has lately seemed. Emboldened by Federal Reserve stimulus, vaccines and the psychological conditioning that arises when no bad patch lasts, everyone from retail newbies to