Many financial “gurus” advise home owners to make lump sum payments on their mortgages and pay them down sooner rather than later. I agree with this to an extent. However I worry people may be under estimating the power of opportunity cost here. Let’s work through the numbers and look at some facts instead of listening to main stream opinions.

Let’s say we won the lottery （●＾o＾●） and became $100,000 richer! Let’s decide if we want to put this money towards the down payment for a house in order to have a smaller mortgage, OR, invest all our winnings in the stock market index and take on a bigger mortgage.

First we must find out what is the cost of borrowing $100,000. Assuming our mortgage rate was 7% every year, by the time we pay off a $100,000 mortgage over 25 years, we would have paid a total of about $210,000 (according to RBC’s calculator). Which means we will be paying $110,000 in interest alone. So if we increase our down payment by $100,000, we save $110,000 on interest in the long run.

But now let’s see what happens if we invest all of that $100,000 into the stock market index instead. Let’s say over 25 years we make an average of 6% a year. In the end our $100,000 would turn into roughly $429,000. But since we invested our $100,000 instead of adding it to our down payment, we have to borrow $100,000 more for our mortgage. From the last paragraph we know the cost of taking on an additional $100,000 mortgage loan will cost us $210,000 total (including interest.) So if we then took our stock investments after 25 years ($429,000), and paid off the extra cost of having a bigger mortgage ($210,000), we would still walk away with a $219,000 profit, in addition to paying off our mortgage as planned! Hey-Ooh! (^o^) Below is a chart of our investment returns.

In the first example we left extra capital sitting in our house doing nothing, except to save us 110% in interest. In the second example, we invested that capital instead so we paid the 110% interest over 25 years, but also made 429% on our investments during the same time using the same capital. So maybe investing our money instead of aggressively tackling our mortgage isn’t such a bad idea.

But wait a minute. What accounting sorcery is at play here when a 6% investment return can dramatically outperform a 7% mortgage rate? Well I’m sure you’ve figure it out by now (^_-) Each time we make a mortgage payment, our principle decreases. It’s the opposite of compound interest, because we pay less interest each time until eventually the entire loan is paid off. But our investment returns on the other hand are the exact opposite and actually compound and grow each year. Annual Compounding x 25 years = major win.

But it gets better! Our mortgage calculations are based on a 7% interest rate which is higher than average, even compared with long term historical rates. Not to mention rates are super low today. So chances are we’ll probably end up paying a lower rate than 7% on average. A cheaper borrowing cost means we’ll end up even further ahead.

But wait, there’s more! I used 6% for our investment returns to be on the conservative side. But North American equity markets have historically returned about 10% annually, and bonds average about 8% annually. Market returns are not guaranteed, but as long as we can average more than 3.1% return for our investments (since that will give us $210,000 which is equal to the cost of the mortgage) then we’ll be better off investing all of our extra cash, than trying to pay down the mortgage. The worst total return ever for any 20 year period in the history of the stock market is positive 3.1%, which was around the Great Depression years. What do you think are the chances of a balanced portfolio averaging less than 3.1% annual return over the next 25 years? And are you willing to miss out on such a great risk to reward opportunity.

But it gets even BETTER! The interest paid on the $100,000 mortgage loan can be made completely tax deductible. Just use the $100,000 as part of the initial down payment first. Then take that $100,000 out as a home equity loan to invest in stocks, and now the interest on the loan can be claimed for investment proposes. So if your marginal tax rate in the 30% tax bracket like me then that 7% mortgage rate has just automagically dropped down to 4.9%. Meanwhile, our investment returns from capital gains and dividends such as gains from the home later are taxed at a lower rate than our marginal tax rate (less than 30% for.) What a bargain! ( ^^) Even the government is giving us an incentive to invest via other people’s money because interest we pay on a loan for investment purposes is tax deductible.

And don’t forget about Inflation! If we stash away $100 under your beds today then by next year it will probably only be worth $98 or whatever. What happened to the $2? Inflation happened. The rising cost of living can be a pain, but it can also be a gift to people who have debt. If you owe the bank $100 for example, then by next year if you haven’t touched the principle, that $100 balance you owe will only have $98 of purchasing power which means it’s EASIER for you to pay it back. So a $100,000 mortgage, assuming a 2% inflation rate, will only be worth $98,000 by next year. Wow, we just increased our wealth by $2,000 in REAL terms by simply sitting on a mortgage :D The bigger our mortgage the more we’ll benefit. Thank you inflation! The US has over $16 trillion of national debt. And its growing by billions of dollars every day because their government continues to spend more than they take in. Inflation is a method used by many central banks around the world to deal with their nation’s debts. They print money so their currency won’t be worth as much. Inflation will slowly chip away at debt, which will decrease the debt’s real value over time making it easier to pay back  Debt is a depreciating liability, but real estate is an appreciating asset, double win!

Finally here’s one last secret. We used a 25 year amortization period. Think about how much more our investment returns can grow if we gave it 30 years to compound instead. A longer time horizon will also decrease our investment risk. For the record, my current mortgage is amortized for 35 years (ʘ‿ʘ) The longer we spread it out the better our returns will be.

So when people say they want to increase their mortgage payments by $500 a month, or make a lump sum payment of $10,000, or aim to pay off their mortgage 10 years in advance, it all sounds good on paper, but I hope they understand just how much money they’re potentially NOT making by doing those things. That said, borrowing money from a home, or investing rather than paying down debt, will increase your financial risk. We are talking about leverage after all, which is what a mortgage is. So if you don’t want to risk losing your home, or not being able to finance the extra debt, then please pay off your house as soon as you can. But if you want to live dangerously like me (o_O) and don’t mind the risk, then invest your extra cash instead of leaving it tied up in your home. Focus on investing and only make the minimum payments on your mortgage, and by the time you retire there’s a pretty good chance that you’ll be better off than other home owners who only prioritize on paying off their mortgages.

• stock market index - A weighted average of some of the largest and most popular stocks. An ETF that one can buy to track this performance would be the IVV for example.
• capital - Money which can be put to good use
• 30% tax bracket - In Canada, if your annual income is between $40K and $70K then there’s a good chance your marginal tax rate is around 30%.
•  leverage - Borrowing money to buy something or to invest