Is it possible for someone under the age of 21 to trade US penny stocks/OTC?

The minimum age to open an account is 18. Customers between the ages of 18 and 21 are eligible to trade stocks in a Cash Account provided they meet all other requirements. For further details on Trade Requirements, please visit the IBKR website…

When you see the message "No opening trades: ineligible PINK stock" it means an opening order for that contract is not allowed, even if your account has trading permissions for US Penny Stocks.

Additional Information…

All clients are eligible for Level 1 options trading permissions. However, IBKR requires that clients be at least 21 years of age to be eligible for level 2-4 option trading.

---…

Yes, IBKR offers trading on the Pink Sheets and OTC stocks that are registered with the SEC.

Additional Information…