Some of our users have asked us about seeing the differences between OS prices and broker prices. Most of the difference is due to the fact that OS uses MID prices to calculate spreads and the brokers (for example Thinkorswim or Tastyworks) use the Conservative prices and use the bid-ask prices against you (so you can trade on market at that price). This difference can sometimes be noticeable when calculating Iron Condors (4 legs) and scanning the entire market (about 4000 stocks).
To solve this there are 2 ways we recommend:
1. Use the bid-ask level setting: This filter lets you control the scanner so you can scan by the conservative way (so the bid-ask prices are calculated against you: buy at ask and sell at bid) or by 25% price improvement. Go to the 'add filter' window and search for 'bid-ask' and you can pick the filter. See the gif above.
2. Negotiate the price with the market makers: Market makers will often stand at a predetermined spread. However, there are constantly monitoring the book and will execute trades that suit them even between the bid-ask prices. To do that, you can set the initial price at mid, and slowly adjust the price 'against you' every few seconds/minutes.
It depends on the market conditions, but we sometimes use a 25% price improvement in our scans, but we always negotiate with the market makers.