The paid (Unlimited) account provides much more market data. Does this have any effect on the simulated market fill price when paper trading?
That is, does paying give me a closer approximation to live trading?
@SteveWired One’s market data subscription has no impact on trading either in paper or live accounts. In paper simulations, fills are at the SIP full market NBBO quote prices (ie buys fill at the ask and sells fill at the bid). In live trading, orders generally fill at the quote prices but sometimes can be a bit better, so paper trading is generally a very close approximation to live trading.
There are a couple of areas however where paper trading doesn’t mimic live trading very well. One is OPG and CLS orders. These fill at the quote just like a market order and not at the open and close auctions the way they would in live trading. Also, paper fills will probably experience a larger percentage of partial fills. Though the orders will ultimately fill, paper trading may take several partial fills to do that while live trading may fill all at once.
So no, paying for a Market Data subscription will not provide a closer approximation to live trading?
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Thank you @Dan_Whitnable_Alpaca !