IEX Group, the start-up stock-trading venue featured in Michael Lewis' book "Flash Boys," hired a former New York Stock Exchange official as chief regulatory officer, the last piece of its senior management team as it moves to become an exchange later this year, the company said on Monday.

Claudia Crowley, a long-time executive with NYSE and affiliated companies, has been working as a consultant for IEX as the firm writes the rules and prepares its regulatory filing for the new exchange that it hopes will be operational by the third quarter.

Crowley starts April 1, the same day that IEX will roll out non-protected displayed quotes, a step in easing the alternative trading system into exchange status. Displayed quotes at exchanges are protected, which requires an order to be routed to the exchange with the best price. Quotes in ATSs, or dark pools, are typically not "lit," or displayed.

Crowley will be IEX's main contact on regulatory issues with the Securities and Exchange Commission and the broker watchdog Financial Industry Regulatory Authority (FINRA).

With her appointment, IEX has filled its senior management team, though Chief Operating Officer John Schwall said a person dedicated to market surveillance also will be hired. That person would report to Crowley, he said.

IEX plans to conduct its own market surveillance, a function FINRA oversees at most exchanges and will also do at IEX, along with the cross-market surveillance it does across all markets.

Crowley also has been working on a third-party regulatory audit of Nasdaq OMX Group Inc's BX exchange, pursuant to a 2007 SEC action against the former Boston Stock Exchange before Nasdaq acquired it in 2008.

Crowley was brought on as a consultant by John Ramsay, a former director of the Division of Trading and Markets at the SEC who became part of IEX's executive team in July 2014 after leaving the commission earlier that year.

Crowley said she was excited about working at IEX, where as a start-up the day is not consumed by meetings, as it seems to be at larger firms.

"It's a paradigm shift and I'd like to be part of the evolution of the market that IEX is building," she said.