Just to keep this updated, there are a lot of regulatory disclosures being fired out by Inmarsat now. So I'm just keeping track of the hedge fund related ones.
Marshall Wace, which is very active on the short side in the UK, now has a 2.38% long position using derivatives.
Melqart Asset Management, one of the firms that was active around GKN/Melrose, has a 1.17% long position, again using derivatives.
UPDATE: Citadel now has a 1.95% long position, again using derivatives, plus 0.16% short.
Plus Pelham has 1.82% long derivative position I blogged on Monday. So around 7% in long derivative positions held by hedge funds in total so far, just in terms of what we can see (I'm not sure what the disclosure threshold is). I expect this will rise. Presumably these positions are offset by a counter party bank holding actual Inmarsat shares, so we might see them start cropping up on the register as major shareholders as was the case with GKN.
Also worth clocking that some more funds have outstanding short positions in Inmarsat. In addition to the names on the FCA list, regulatory disclosures show that Renaissance Technologies and Millennium Investment Management both have short positions of just under 0.5%.