Personal Sweep Accounts

Yes. Most of the big banks. Read the disclosures. For lines tied to checking accounts for automatic overdraft protection, not only is it higher rates, but banks now charge a transfer fee. Some lines that require you to initiate the transfer on you own through online or mobile banking don't have the fee. You'll probably be able to find a community bank to do it without the fee because they are typically slow to adopt those types of changes.

ETA: If you're looking for a name, Citi does it for sure.

No offense, you can call it whatever you want, but that's what it is.

Sweep accounts go in the opposite direction. Any balance over a certain amount gets swept into a product with a higher interest rate.

The purpose of revolving lines of credit (or any debt product for that matter) is to meet current cash shortages due to a timing difference. That's the key -- timing differences. The cash has to be available in the future to repay the debt product otherwise it's insolvency. An overdraft is a form of a cash shortage due to a timing difference. Banks charge the transfer fee to make up for the overdraft fee.

If I have drawn more on the line than cash, then I have a cash shortage. If I have more cash than I have drawn on the line, then why am I paying interest?

For downside protection, I've got a $10,000 unsecured line tied to a checking account. The available balance always shows whatever cash I have in the account plus the $10,000. If drawn on and as funds are deposited, the line is paid down automatically (at a local bank BTW). For upside protection, I sweep balances that are greater than 90 days of operating expenses.