Okay, let's do some math:

Citadel and partners paid in total 2.55b.  800mil of it goes outright
to buy ABS.  This means the remainder 1.75 billion went to buy shares
and convertible bonds.  Now, Citadel folks are real bastards, so they
covered themselves by having a mix of shares and bonds, so they have
secured stream of income in case things goes sour.  But the upshot,
according to Bloomberg, is that :
"In total, the group will get shares worth 19.99 percent of the common
stock currently outstanding."

Okay, according to google finance, there are 423 million shares
outstanding.  20% of that is 86.6 million shares.

1.75 billion divided by 86.6 million is 20.2.  This means that Citadel
and Partners paid $20.2 per share

Okay, part of it was convertible bond, which means the interest
depreciates some of the values, so that affects valuation....etc.  I
am not sure what is the exact math, but even if Citadels are great
negotiators and stick all kinds of clauses into the deal, at least
they paid $10 a share.