It's been quite a month for @Jack.
Square, the payments company that Dorsey launched three years later, has performed even better, surging nearly 24 percent for the month to a record $58.90 as of Thursday morning.
Dorsey has been as much a beneficiary as anyone. His stake in Square has jumped by $668 million this month, and his Twitter shares have appreciated by $65 million.
As May comes to an end, Square is worth $23.6 billion, not far behind Twitter's $26 billion stock market value. After years of skepticism, Wall Street has apparently come around to the idea of the 41-year-old Dorsey running two publicly traded companies at the same time.
When Dorsey took over Twitter from Dick Costolo in 2015, it was supposed to be temporary. At the time, Dorsey had his hands full with Square, which was preparing for its stock market debut and was having trouble justifying its private market valuation to prospective investors.