“Supposedly” is the standard form. “Supposably” can be used only whenthe meaning is “capable of being supposed,” and then only in the US.You won’t get into trouble if you stick with “supposedly."
DirecTV Is Supposedly Buying Hulu If it seems like Hulu's been up for sale for a few years now that's because it totally has been. Seriously, back in August 2011 we tried to figure out which Hulu bidder we should be rooting for. And then in September 2011, Dish Network was rumored to buy it . Well? Nothing happened. Now nearly two years later, DirecTV is supposedly in pole position to snag Hulu. Read more...
June 14, 2013 - Gizmodo
Five Questions Heading into the U.S. Open at Merion It's finally here: the U.S. Open, the second major, golf's supposedly toughest test of the year, and it's back at Merion, the place where Ben Hogan hit the most famous 1-iron of all time and where Lee Trevino once outdueled Jack.
June 13, 2013 - Yahoo! Contributor Network via Yahoo! Sports