The superrich blueprint to navigating this hairy stock market: Tap the brakes and get ready to pounce when it all goes to hell. And by the looks of Monday’s action, hell might not be too far away. In the first quarter, Tiger 21, a coalition of 750 members worth in excess of $75 billion, raised cash to levels not seen since 2013. Not much changed in the second quarter in terms of keeping powder dry. The group’s holding 12% in cash. What has changed, however, is that these deep-pocketed investors, in the call of the day, are continuing to move...