It looks like the biggest IPO of the year will bring over $250 million

Bats Global Markets has priced its initial public offering at $19, CNBC reports, citing Dow Jones.

It's set to raise about $253 million, making it largest IPO of the year.

The stock exchange operator is set to begin trading Friday morning on its own Bats BZX Exchange.

Shares were expected to price between $17 and $19.

Bats is the second-largest stock-exchange operator in the US, after the NYSE. It holds a 21.1% share of the US equities market, ahead of Nasdaq's 18.8%.

It operates the largest ETF market in the world, with a 26.8% share of that market, ahead of both Nasdaq and the NYSE.

Bats also operates the largest exchange in Europe - larger than the Deutsche Borse and the London Stock Exchange.

The Bats deal - which will be listed on one of Bats' own exchanges, the BZX Exchange, under the symbol "BATS" - is actually the company's second attempt at going public.

Back in 2012, Bats had to withdraw its first IPO attempt after its computers malfunctioned and kept its stock from trading. They also forced a circuit breaker in Apple's stock that day.

But things are expected to go a lot more smoothly this time. Bats has listed 70 exchange-traded funds on its exchanges since then, and performs auctions daily in each of those securities. It had listed only nine at the time of the first attempt.

It has also run more than 50,000 tests of the corporate-auction mechanism in recent months, according to someone who attended the Bats roadshow presentation, and has tested the system up to nearly as much as three times the auction volume of Facebook's IPO, the largest IPO in history.

More to come...