Jack Dorsey made $300M on Square today

Square hits the market: Sell or buy?
Dorsey: Square strong in everyday transactions
Square surges in debut

Square's surge Thursday may make its CEO and co-founder, Jack Dorsey, forget all about Twitter's drubbing this year.

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.

Jack Dorsey (L), CEO of Square and CEO of Twitter, live casts video while standing outside the New York Stock Exchange for the IPO of Square, in New York November 19, 2015.
Lucas Jackson | Reuters

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.

Jack Dorsey (C), CEO of Square and CEO of Twitter, is congratulated on the floor of the New York Stock Exchange after the IPO of Square Inc., in New York November 19, 2015.
Square ends its first day of trade up 45%

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.