12. Nick Themelis
Chief Information Officer
MarketAxess Holdings
Last year: 13

After yet another record-shattering year, executives of the fixed-income trading, data, and posttrade services provider MarketAxess Holdings aren't conceding any limits to the company's growth potential — or the power of its technology. In business since 2000, publicly held since 2004, and with Nick Themelis as chief information officer since 2005, MarketAxess' electronic platform claimed a 17.2 percent share of U.S. high-grade corporate bond trading in 2016's fourth quarter, up from 15.1 percent a year earlier. Its total global, full-year trading volume of $1.3 trillion was 33.7 percent higher than in 2015, while revenue climbed 22 percent to $369.9 million, and pretax income rose 29.5 percent to $191 million.

Helping to fuel that success, and accounting for 13 percent of trading volume, is one of the most talked about bond market innovations: the Open Trading protocol, which MarketAxess introduced in 2012 and is currently approaching $1 billion in daily volume after 86 percent growth last year. "Open Trading was a response to the market's liquidity problems," Themelis, 53, explains. "We connect every point of liquidity," buy-side and sell-side, in a so-called all-to-all trading pool that in 2016 saved liquidity takers an estimated $100 million-plus in transaction costs.

Themelis, a former Barclays Capital CIO for North America and global head of fixed-income technology, believes it will be hard for a competitor to match MarketAxess' first-mover advantage, notably its connected community of more than 1,100 buy- and sell-side participants that is responsible for Open Trading's momentum. Those users are requesting that the protocol be extended into municipal bonds and other asset classes.

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