Only legacy address space is frequently bought and sold, so it moves between AS#s a lot and is also heavily fragmented.
With v6 this is not the case, a given AS# will typically have a single large allocation and can make it larger if they need to, it won't be sold and moved and an entity can't trade it in to get a different allocation.
With v6 this is not the case, a given AS# will typically have a single large allocation and can make it larger if they need to, it won't be sold and moved and an entity can't trade it in to get a different allocation.