This is exactly why I was happy to find an interest-only jumbo mortgage at 3.xx% back in the crazy loan times (2006). Keeping that money in the investment portf

This is exactly why I was happy to find an interest-only jumbo mortgage at 3.xx% back in the crazy loan times (2006). Keeping that money in the investment portfolio, thus returning X minus 3.xx%, was significant. So you’re quite right, and it works in real life. But! It’s essentially margin risk — don’t do it if your investments aren’t comfortably larger than your mortgage.