The Russell is a set of stocks that comprise an index, like the DJIA or the S&P 500, not an exchange like NASDAQ or AMEX or NYSE. NEOP will continue to trade on the same exchange.
By being included in the index, NEOP will HAVE TO be bought by mutual funds set up to mirror the performance of that index (there are funds that track the Russel 2000 or 3000, attempting to mirror the overall performance of the small cap world, just as there are funds that mirror the DJIA components or the S&P 500).
The funds that track the Russel index, which by definition don't own NEOP now, as it has not been a Russel component before now, will need to buy NEOP. The funds will "rebalance" so that the dollar value of their holdings mirrors the composition of the Russell index in % terms (i.e. if NEOP were deemed to be x% of the total market cap of all 3000 stocks in the Russell 3000, then each fund tracking that index would buy NEOP to the point at which the fund had x% of its capital in NEOP).
The effect is three-fold
1. There is immediate buying of NEOP from these funds (they generally give themselves a couple weeks to get rebalanced--selling the stocks no longer in the index, buying the new ones, and adjusting those retained to the correct new proportions).
2. The funds sit on those shares until at least the next rebalancing. As such those shares, while technically still part of the float, are in fact now held by the index funds and not actively traded, are for practical purposes locked away and not for sale, which reduces the "effective float" of shares available to be traded.
3. These shares are now in "strong" hands from which they will not be shaken out by news, price declines, FDA delays or even fishy FDA Citizens Petitions written by self-serving short sellers.
All 3 impacts are positive for NEOP and NEOP longs.