When I bought a house I had to prove the 20% down was not via debt like a line of credit. Perhaps they would require something similar.

The problem with that is, once you have a mortgage, everything is in effect a line of credit until it is paid off.

Depends on your mortgage. Five years fixed at 2.99% means that it’s often smarter for me to invest the money in a GIC at 4.60% rather than pay it off.

(The risk of course being when I renew and it’s way higher)

In the US yes because of tax relief and better investment options? Here I pay nearer 4% mortgage (a 3% 5 year fix like your may have been possible with impeccable timing, just got off a 4.39% 5 year fix), in after tax money, get maybe tops 1% in the bank and have to pay tax on that 1% too!

Technically you can pay off some of the mortgage early, split a new loan account, borrow from that new account, and then use that to invest, and claim the interest of that against tax. So basically those with more money pay less tax, of course.

Canada. And indeed there’s lots of clever tricks like that. I’ve opted lately to put the blinders on, stop gaming the system, and just get out of debt so I’m making extra payments and whatnot.