I hadn't heard of this although I'm in the industry.<p>It sounds weird. Normally if you want to attract or profit from high frequency traders, you offer the differential product (fast market data / colocation / direct exchange connection) to <i>whomever is willing to pay</i> and then you take pains to equalise latency between those participants. That's usually what both the market and the regulators want.<p>If you assume collusion with trading firms, privately offering special services to a handful of participants also doesn't make sense - better to do deal with one, who would pay more for the exclusivity and be less likely to publicly expose you. For a top market maker, competing with 50 others isn't much worse than competing with 5 others, but they might pay millions a month to have zero competitors.<p>So, ruling out bad business or corruption, what's left? It sounds like it might just be a compliance failure by Nasdaq: they marketed the feature to the obvious firms, the ones who were already paying for the fastest service, and neglected to do the right regulatory filings to advertise it to everyone. Which is not nothing - regulators enforce transparency on this thing for good reason - but is pretty close to a victimless crime.