When the orders were added, there was a modification to the FIX specification for the exchange. For example: http://www.directedge.com/Portals/0/docs/Direct%20Edge%20Nex.... It is everyone who trades on that exchange's responsibility to stay up to date with what's available, and how it interacts with their trading strategy.
"concealed", in this context, just means "too lazy to carefully read the documentation".
Comments
False - HFT firms have access to special order types. Example is Hide Not Slide, which is mentioned in the book and also here [0].
[0] http://online.wsj.com/news/articles/SB1000087239639044398920...
Why do you believe only HFTs have access to hide not slide? That order type is plainly listed on DirectEdge's website, e.g. https://www.directedge.com/Portals/0/01Trading/Trading%20Pro...
As doktrin said, they were originally concealed.
When the orders were added, there was a modification to the FIX specification for the exchange. For example: http://www.directedge.com/Portals/0/docs/Direct%20Edge%20Nex.... It is everyone who trades on that exchange's responsibility to stay up to date with what's available, and how it interacts with their trading strategy.
"concealed", in this context, just means "too lazy to carefully read the documentation".
[citation needed]
any exchange member may submit a hide-not-slide order. there is nothing secret about them.
They were originally concealed.