GDF and RIG merged. From Briefing.com: The final cash entitlements of the GSF & RIG Common Share components of the OIH are distributed to OIH shareholders with today being the ex-distribution date. The final distribution ratio is $1,043.1785 <$10.43> per 100 share round lot of OIH. I'm still trying to figure out how all this affects me...
A result of ex-date is that the standard 100 share option contracts will NOT trade on ex-date, only the adjusted will trade. Ex +1 the standard 100 shs deliverable will come back for trading in a tapered fashion (5 deviations form ATM). Keep this in mind with rights issues, depending on your position you could stand to get hurt big time.