I have not paid the fee to get on the data feed that FBT provides on their holding changes 3 trading days before rebalance. However, I contacted them and they confirmed that as of the date of my request XON was below their minimum market cap of 900 mill. They also sent me a link to their index rules which I was already aware of but it reinforces they are very objective in their rebalance procedures.
While there may be some subjective allowance for a holding that is very close to the minimum market cap XON was well below the market cap on all but 5 trading days since March 1 after they announced the "going concern" language.
Another concern an index fund would have is their holding % of a company and the extreme trading distortion it can have on rebalance days. FBT with 11+ mill shares owns 7% of XON. If XON were kept in the index the number of shares needed to be purchased based on today's close of 4.44 would bump the ownership up to 22 + mill shares and 14% ownership. That level of ownership would add a whole new level of SEC reporting requirements. Why go through that hassle for a holding that is already below the minimum market cap?
Don't hesitate to ask questions. We should all be helping share info on these boards. I just don't come here often enough to have answered your question as promptly as you might expect.
I was replying to Tim more to indicate all the stocks that will be affected tomorrow (Thursday) so people aren't surprised by increased volume on the close.