[bd_at_rivenhill]

I know that ISE had some sort of automatic cancellation feature from the beginning or very close to the beginning, so not sure if PHLX was the originator of this idea. Also, nearly all electronic options exchanges have a "mass quote" feature that allows changes in prices over a large number instruments at the same time. I would expect that this feature is available on every US exchange and only a few overseas exchanges lack it, and managing the generation of mass quotes vs exchange message rate limits is one of the more complicated parts of designing option quoting systems. Finally, there is also a "cancel by underlying" feature that cancels all options on a specific underlying; if it is the case that the mass quote doesn't allow quotes to be cancelled (i.e. modified to 0 size), then the usual approach is to cancel by underlying and then immediately requote at the new price level.