interesting development here. IB now offers a "Integrated Financial Management Account" that includes a debit Master Card. Using the card will create a margin loan in your IB account, with IB's rock-bottom margin interest rates. Peterffy is personally promoting it in a video: ibkr.com/message With it, IB starts to extend its reach and customer-friendly rates into the banking industry. Using an IB-linked debit card is clearly a better option than using a high-interest credit card (with potential late payment penalties etc.). And maybe this also helps IB to sign up new customers who especially value this combination, like asset-rich folks who have been wooed by Wall Street banks with margin loans (no doubt at much higher rates than IB is offering). However, we'll also likely have to prepare ourselves for tales of customers who will complain that IB made it too easy for them to irresponsibly spend away their savings.