$277M birthday gift? Square's Dorsey got one

It's not often you get a $283 million windfall on your birthday. But Square's CEO just did.

Jack Dorsey, the co-founder and head of the mobile payments company who also turned 39 today, just saw the value of his 69.6 million shares of the company skyrocket along with share of the company on their first day of trading Thursday. Shares of Square jumped $4.07 to $13.07 - taking Dorsey's stake in the company to $910 million.

Dorsey is the largest owner of Square, which is a San Francisco-based company that allows merchants to process credit card payments. Shares were sold to initial investors at $9 a share, which was below the $11 to $13 a share range expected. But Dorsey didn't sell any shares at that price, so he's enjoying the full power of the first day trading. Good move, Jack.

The day's action on Square easily puts Dorsey in the billionaire tech club. Dorsey also owns 21.9 million shares of Twitter (TWTR) which are currently valued at $576 million. Adding that to the Square stake brings Dorsey's worth from just those two companies to $1.5 billion.

Happy birthday indeed.

BIGGEST OWNERS OF SQUARE AND HOW MUCH THEY MADE ON IPO

Holder, Common stock owned (millions), $ gain Thursday ($ millions)

Jack Dorsey, 69.6, $283.3

Khosla Ventures, 50.5, $205.5

James Morgan McKelvey, 27.3, $111.1

Rizvi Traverse, 15.9, $64.7

Sequoia Capital, 15.7, $63.9

Source: S&P Capital IQ