Shares of the mobile payment company soared 45 percent in their public debut, netting Dorsey a roughly $300 million paper gain. Dorsey — who currently heads both Square and Twitter — saw his net worth top $1.5 billion Thursday in stock value alone.
Square opened at $11.20 per share Thursday after pricing at $9 a share, below the company's initial expected range of $11 to $13 a share. The stock closed the day at $13.07 per share.
At that price, Dorsey's more than 71 million shares were worth about $930 million. Taking away their value at the $9 per share IPO price, Dorsey made $289 million on Thursday alone.
At Twitter's closing price of $26.32 per share Thursday afternoon, Dorsey's stake in the social media company was valued at about $575 million. Dorsey's stock in the two firms amounted to more than $1.5 billion on Thursday.
Dorsey's pay from the companies adds little to his net worth. He took in a salary of only $3,750 at Square last year, and currently makes nothing at Twitter.
Still, Dorsey does not plan to hold all of the shares he owns currently. In a filing with the Securities and Exchange Commission, he said he plans to give 40 million shares to a foundation that invests in artists and small businesses.
It was unclear whether the donated shares were subtracted from the stake disclosed to the SEC.