I've read something different, and probably i'm wrong, but:
The FXCM Newco was the "bad company" in the old agreement, only to manage the non-core assets sale.
The existing FXCM Newco, LLC (“Newco”) agreement would be amended, Newco would be renamed FXCM Group LLC (“FXCM Group”), and Leucadia would own a 49.9% common membership interest in FXCM Group. FXCM Holdings LLC would own a 50.1% common membership interest in FXCM Group.
For sure, i would like to read all the agreement.