I'm wondering if this investment strategy would work:

1. I get a mortgage loan for $300K at a 3% rate (realistic for current 5-year fixed mortgage rates here in Canada).

2. I invest the proceeds in a low-fee index fund, such as Vanguard's Total Stock Market Index.

3. I use the interest to cover the mortgage payments, and invest the rest of the returns.

This looks like it could work. Am I missing anything?

Thanks!