IBKR T&S FINRA on exchange

External question — Personal Finance Stack Exchange Author: David Original post: https://money.stackexchange.com/questions/159381 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I've opened the T&S table in IBKR and I've seen in the "Exchange" column a lot of entries with the name "FINRA". I've googled what it is and it stands for Financial Industry Regulatory Authority. Is it right to say that it's not an actual exchange ? What does it have with OTC trades and what are those exactly ? The question is : If a stock has a lot of FINRA entries in the Exchange column, does that mean that it's harder to get filled on normal exchange such as NYSE/MEMX/DIRECTED EDGE/EDGEA, etc. ? With a stock with so much volume and trades made per second, it takes me so much time to get filled when I place a limit order to buy at the bid using either by using SMART or by placing in on an exchange that I see many people use on that stock such as NYSE or EDGE (longer than 5-6 minutes to get a fill). Why does this happen ?