I used margin to buy a house for my DD and SIL, at very good rates. I opened an IBKR account, let it season for a month, then borrowed on margin $243,000 at 1.52%. My margin percentage was a little bit under 40%, but I got advice from Pete at MMM that I might want to get a Heloc to pay that percentage down, in case the market dropped. So I did that, went to banker , Saying I'd like to get a HELOC, I don't have a job I have no regular income, but I did get the HELOC with just showing the statements from my Vangard accounts, IRAs and Roths, I may have shown my IBKR account, but I don't think so, I find there webpages hard to decipher, but not so hard that I couldn't figure out how get money on margin. Nice surprise, the Bank HELOC teaser was 0.99% for 6 months then jumped to 3.99%. So, my blended interest rate was 1.26%. Now, dad's not a dummy, this was a fixer upper house, so I gave the kids a mortgage at 4% the first year and as a get your a$$ in gear, 6% for the second year. They fixed the house and mortgaged it in 10 months, I got my money and paid off all the loans.
I'm sure rates have risen a little since I margined in July of 2021 and got my Heloc in Sept 2021, The mortgage I held was paid off May 13, 2022
Here is where I got the idea and more details about it.
https://www.mrmoneymustache.com/2021/01/29/margin-loan-ibkr-review/
Just looked at the IBKR site, Rate have exploded, 3.58% for $100k to $1M.
https://www.interactivebrokers.com/en/trading/margin-rates.php