Near as I can tell, fees will be high enough so as to make the arbitrage unprofitable.
I believe the mechanism going on here is this:
Big Traders offer to buy at $10.00 on Light Pool. Their offer sits there, and gets filled slowly over time. Then, for whatever reason the price moves, and a bunch of speed traders try to sell on INET/ARCA/BATS at $9.99 (perhaps in anticipation of the market moving down to $9.90). Due to the high fees, they don't place those orders on Light Pool. The market crosses for a little while, no trades occur, and Big Traders get the opportunity to pull their $10.00 order from light pool.
However, the article wasn't clear enough for me to be certain.
I believe the mechanism going on here is this:
Big Traders offer to buy at $10.00 on Light Pool. Their offer sits there, and gets filled slowly over time. Then, for whatever reason the price moves, and a bunch of speed traders try to sell on INET/ARCA/BATS at $9.99 (perhaps in anticipation of the market moving down to $9.90). Due to the high fees, they don't place those orders on Light Pool. The market crosses for a little while, no trades occur, and Big Traders get the opportunity to pull their $10.00 order from light pool.
However, the article wasn't clear enough for me to be certain.