PALO ALTO, CALIF.—Elon Musk will remain at Tesla under a 10-year, all-or-nothing pay package that demands massive growth. The agreement, revealed Tuesday in a regulatory filing, requires that Tesla grow in $50 billion leaps, to a staggering $650 billion market capitalization. To put those demands in perspective, the electric carmaker, based in Palo Alto, California, is worth less than $60 billion today. Tesla must hit a series of escalating revenue and adjusted profit targets, only after which Musk would vest stock options worth 1 per cent of company shares. If the goals are reached, Tesla will be one of the biggest companies in America, and it Musk’s wealth would grow exponentially.