The best I can make is that they were dropped from some Alerian mlp index in favor of another outfit in the same business. This might have brought a lot of shares to sell from the index. If somebody here has better info, please share.
Good time to buy more Inergy stock. From what I read on Boards and market comments, they expect to grow their dividend annually by 6% or more. The midstream business is very stable and some analysts forecast the price to be in the 20s in the near term.