When you open a Lumina account, you're also opening a brokerage account at Interactive Brokers (Nasdaq: IBKR). Lumina is a registered introducing broker; Interactive Brokers is the clearing firm that carries your account. You use Lumina, and IBKR does the heavy lifting underneath.
What IBKR handles
Custody of your money. Funds sit at IBKR, segregated from the broker's own funds under CFTC rules and reconciled daily (see Where your money is held).
Application checks. Identity verification, anti-money-laundering screening, and bank-account verification during your application are run by IBKR, not Lumina.
Money movement. Deposits, withdrawals, and the fees on extra withdrawals are processed and charged by IBKR.
Records. Your activity statements, trade confirmations, and official tax forms are IBKR-generated (see Taxes and documents).
Why this setup
IBKR has operated since 1978, is publicly listed on Nasdaq, holds over $20 billion in equity capital, and is regulated by the SEC, FINRA, and CFTC. Pairing Lumina's trading experience with that infrastructure means a new platform doesn't ask you to trust a new custodian: the firm holding your money has been doing exactly that for decades, at scale, under regulatory supervision.
The relationship, plainly
Lumina and Interactive Brokers are affiliated companies under common ownership; the relationship is described in our Conflict of Interest Disclosure. Day to day it means one application, one app, and one login, with your account and funds carried at IBKR.
What it means when something goes slowly
Because approval decisions, document review, and money movement happen at IBKR, some things aren't instant on Lumina's side: applications can go to review, and transfers settle in batches. The articles for those moments: Stuck in the application? and My deposit didn't complete.