The SEC Proposed a Tick Constrained Spread

Right now the more narrow you can quote is a penny wide, meaning I'll be bidding 9.99 to buy a stock and someone offers to sell a 10. The argument is that there's so many people aggregating at the 9.99 and the 10 price point that if there was a price point between 99 and 10, there'd be the ability for people to narrow those spreads. And part of the idea here is to put exchanges in a better position to compete with ochos.