Shares of Alphabet, the parent company of Google, crashed 13% in Thursday’s trade on October 29, falling to an intraday low of $280 apiece, as Wall Street was disappointed with the company’s September-quarter performance, particularly in its core search advertising business, while its cash burn extended into the second quarter.If sustained through the close, the decline would mark the stock’s worst single-day drop since it began trading more than 20 years ago.