![CBOE is still one of the few exchanges to operate an open outcry floor](https://assets.fnlondon.com/2016/09/IMG012826_full4x3.jpg)
Two major US exchange groups, CBOE Holdings and Bats Global Markets, are reportedly in talks over the global exchange sector's latest multibillion-dollar merger.
Chicago-based CBOE, which operates in the lucrative US equity options market and owns the popular Vix volatility indices, would be the bigger party in any deal, with a valuation of around $5.6 billion.