This is the least-read page in personal finance. It controls real money. Let me make it quick.
Margin loan rates compared by balance tier: brokers slice borrowing into bands. Under $10,000 might cost 11%. From $10,000 to $25,000, 10%. Above $100,000, maybe 8.5%. The bands differ at every broker. The breakpoints differ. And the advertised rate is always the cheapest band, the one for the biggest borrowers. Marketing 101.
Which creates weird outcomes. Broker A advertises 8% and Broker B advertises 9%, and for your $30,000 balance Broker B is cheaper, because its tiers are kinder at the bottom. You would never know without the tier table. Almost nobody checks the tier table.
Interactive Brokers tiered margin rates get cited constantly because their published tiers are genuinely aggressive, especially as balances grow. Worth knowing. But run your own numbers at your own balance. Reputation is not a rate.
Practical rule: if you will borrow less than $50,000, ignore the lowest margin rates broker headline and compare only the bottom two tiers. That is the only part of the schedule that will ever apply to you.
Two modern helpers. A broker fee alert app with push notifications can tell you when a broker changes its margin tiers. Schedules do move, and the change never arrives with a trumpet. And a fee audit calculator SaaS can re-price your balance across brokers in minutes instead of an afternoon with PDFs.
While you are in the schedule, glance at account closure and inactivity fees by broker. If you ever deleverage and let the account sit idle, you want to know whether idleness itself gets billed. BrokerCompare publishes margin loan rates compared by balance tier across 50 US brokers, so you can check your band in minutes. Start at brokercompare.fyi.