Quote from resinate:
I don't think this has been mentioned in this thread, and yes, going more electronic will be an interesting change for SPX. From the little I have read of the new system, its a bit different from the existing CBOE hybrid. IBs marketing of additional floor presence in light of hybrid's immanent deployment is curious.
When SPX goes 'index hybrid' on 9/25, there will still be only one electronic quoter, which rotates between 5 large market making firms, so spread width may not change much.
However, booked orders will be able to be traded electronically vs. the current system of floor brokers yelling to order book officials to manually match orders b/t buyer and seller. Therefore this change probably benefits small orders (<10 contracts) as they will trade much faster, and floor brokers will likely keep the larger orders unposted to look for price improvement.