I think the risk of another bidder is minimal. Because of size, Nike is the only other potential suiter.

I am assuming chances of deal occuring are very high because a SEC filing 8K entry into material agreement has been made by rbk and I don't think there are any other potential bidders who are likely to thwart this deal. Furhtermore, the generous premium at $59 a share will likely win the approval of rbk shareholders.

With the stock at $57 a share and the buy out price at $59, the $2 reward for those who hold or jump in now equals about a 3.5% return (2/57). This is slightly higher than what you can get on a high yield online savings account, so what this tells me is that investors are pretty confident in the deal going through because of the low risk premium. I would expect rbk's price to come ever closer to $59 as we get closer to the deal actually occuring. However, any uncertainties or delays that come up will likely produce a good deal of volatility.

Personally, I'd like to get a price closer to $59 before selling.