Robert is spot on. CS has routing deals that include price improvement and hidden liquidity. Most of the stuff goes through Citadel and SIG. They now use the old optionsXpress routing. The old deal was with UBS, but they pretty much saw UBS become not as competitive. Doesn't apply to SPX and VIX. The nice thing about routing deals is the firm will pretty much fix anything. Hidden liquidity - which IMHO shouldn't exist - means you might fill for size larger than display. This keeps the order from shipping. Limit orders are mostly going to go to Maker/Taker platforms - marketable limits to to PFOF platforms. Schwab determines all routing with electronic - phone orders can be routed, but you pay a premium for phone service. On rare occasion you won't trade with a MM and your order could be part of a customer cross, most likely on Maker/Taker venue. You can look at any firms SEC form 606 which shows routing - economics in terms of rebates. The old oX platform is being folded into Schwab now for everything but futures.
"Thanks, I've tried entering a limit buy order at a price that is close to bid, and wait half a minute to see if gets filled. If not, I increase the price by 10 cents and continue. It should get me the best possible price with a limit order, but I didn't try market order on the same option so I don't know where a market." You'll love this - Schwab has an order type that does this automatically. Again a carryover from oX. It's called the "Walk Limit" - frees you up to do something else if you choose.
Interesting. I've never seen that available on the trading page. Can't check that now as somehow the CS web page is not loading, but it sounds like a very useful feature. Thanks!
Here's the old oX explanation. Walk Limit® — Quick Start Guide Print Walk Limit (WL) is an automated limit order that "walks" the client’s order to save them time while attempting to get the best fill prices. A Walk Limit order goes to the market at the initial mid-point of the National Best Bid or Offer (NBBO), rests for 2 seconds, and then cancel/replaces the order a maximum of 11 times until the order is filled or rests as a limit order at the End Price (never outside of initial NBBO). Walk Limit works on all option order types and is customizable, allowing users to specify start/end prices, price increments, and time increments. Walk limit is available for all equity option order types, from single leg options and stock/option orders to multi-leg strategies of up to 4 legs. Walk Limit is located in the All-in-One Trade Ticket which is in the Trade main toolbar.
OTC trades bilaterally. You can have trades posted to the exchange without worrying about your orders destroying price stability. Go to google and type in Tradeweb. "If you have to ask, you're not ready to know yet."
I've seen this automated when spoofing in futures, it'll send thousands of orders in less than a second. It's an incredibly amazing piece of technology when used in the right hands.