Do I need to keep my uninvested cash in my account for a certain length of time in order to earn interest?

IBKR calculates and pays interest on cash balances in accounts as follows:

Interest Eligibility and Rates:…

You may be charged interest even with a positive cash balance due to several factors related to how Interactive Brokers calculates interest:

• Adjusted Cash Balance…

No. The interest you earn under the Stock Yield Enhancement Program is not within scope for Irish WHT obligations. Irish WHT only applies to credit interest paid on uninvested cash balances in your account.

Additional Information…

IBSG clients enrolled in IBKR Lite are subject to the following interest, fees and rates:

• lower interest earned on uninvested cash balances;
• no interest earned on uninvested cash balances that are being posted to IBSG as collateral to meet margin requirements associated with derivative products;…