First, to be clear, wind down is not the same as wind up. (Just wanna get that clear off the bat).
That being said, winding down is not technically outside of the permissive acts of a Conservator when "preserving and conserving" since winding down keeps the Conservatees in operation, but perhaps at a lesser level in order to prevent overexposure to the market that could bankrupt them. So, simply saying "We will wind down" does not go against the preserve and conserve mandate.
Winding Up would go against the preserve and conserve mandate, however...as that would put the Conservatee out of business and they would cease to operate.
And THAT being said, the action that goes against the preserve and conserve mandate is specifically the NWS because it doesn't allow the GSEs to operate at their full potential and goes against the original 2008 contract that put the organization into Conservatorship in the first place.