Thx for your answers, very helpfull, and ajacobson, thx for the link.
It's all about large cap stocks like T, WMT, PG, those kind of stocks.
I understand that it's, in normal cases, impossible to open up 10.000 postitions in a thinly traded stock, or indeed with a price that is totally skewed with reality.
Just wondered, if I buy 1000 pieces of say, WMT, and I want to buy 10 married puts with it, that won't be a problem.
But when 1000 people at the same time, for some reason, will do the same, 1000 x 10 will be 10.000 put contracts, and then I started to wonder......
OI isn't that high, even in stocks like WMT.
How do the big guys protect their positions ?
Can imagine that a guy like Warren Buffett has some kind of protection in his positions ?
There is no such thing as too big. When I was on the floor I use to see 5k and 10k options cross on a single trade. Guys would be tripping over each other to get that business.