What is the cap for movement speed reduction?

If stacking movement speed reducing skills on a target, what is the cap % that you can slow that character, not using skills like Iron Mist or others that slow 90%.

AFAIK this is one of the few mechanics without a cap. You could test it though.

Binding chains ritual skill - chanelling magic cost 15 energy and it slowers opponent's movment by 90% and it isnt elite...for i think somthing like 10 -15 seconds,and oh it also makes opponent unable to attack

White Head, he said excluding skills that slow 90%

I don't see how any could stack as I believe the lowest reduction is 50%. Stacking another 50 or a 60 on top would immobilize the character. I think if you try to stack the highest reduction would be the only one active.

Finally found it on the wiki http://gw.gamewikis.org/wiki/Stacking

"Some effects, like slowing effects and bonuses from runes, do not stack, and only the most powerful effect is taken in to account."

acoording to very recent article on game mechanics, they stack up to 50% nothing higher exept skills like water hexes (66%, 90%)

Posting the answer to my own question for any other interested observer, from GW.com: