# How do banks actually make money on mortgages [closed]

This is a bit of a subjective question and relates primarily to the UK market

There are a number of banks who are lending at BOE + 1.49% (ie: 1.99 %) whilst at the same time accepting deposits paying 2.75%

Granted the 2.75 is a bonus rate but I just cannot understand how writing these kind of mortgages are beneficial froma a banks perspective

EDIT: The terms were in fact on a two year fix with the ability to refinance tpo another provider. The answer to this question was in fact that the bank is able to artifically create moiney by fractional reserve banking and is further able to source funds from the BoE direct.

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## closed as off topic by chrisaycock, goric, Joel Spolsky♦Feb 8 '11 at 19:38

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I removed the "general" tag. – chrisaycock Feb 8 '11 at 14:38
You need to provide more information about the mortgage than just the rate. What are the other terms of this 2% mortgage? Is it a Fix 30, 15, 10 (doubt it)? Is it a 1-month, 1-year, 2-year, etc. ARM? Is it a balloon? Are there prepayment penalties? – Joshua Ulrich Feb 8 '11 at 15:00
This question is really too basic for a professional site on quantitative finance. – Joel Spolsky Feb 8 '11 at 19:40
Actually you will be suprised at how the basics are often misunderstood by people who have worked in the industry for many years. – Jack Kada Oct 1 '14 at 10:30

Most large banks generally sell the mortgages they originate to investors, but they retain the servicing rights. Therefore, they make money via origination and servicing fees; the spread between deposit rates and mortgage loan rates isn't as simple or important as your question suggests.

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Check out the amortization table on your mortgage. You'll find that for the first five years, you are paying 90+% of your payment towards interest. So, if you need to sell end your loan anytime before full maturity, the majority of what you would have paid is interest, not principle. So, your effective interest rate for your specific loan duration would have been much higher.

I don't think this factor is stressed enough, and really ought to be illegal. Why not just divide the interest evenly over the life of the loan so that interest and principle are applied equally? A real shameful way to do business...

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I am no expert of banking, but hope to share my thoughts.

First, bank's capital charge for mortgage is not 100%, so with $100 deposite, banks can lend out, say,$500, depending on the capital charge.

Second, I think the deposit rate and the mortgage rate you mentioned is not the same duration. I am not familar with the rates in UK. It's possible that the deposit rate of 2.75% is, for example, 3 year rate, while the 1.49% mortgage rate is a floating rate (1-month rate). Usually the short term rates are lower than long term rates.

Let me know if I am wrong. Thanks.

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How can they do it? I mean, mortage is an upfront expense for the bank, so they must have 100% of the cash to provide it to the home buyer. – quant_dev Feb 8 '11 at 17:53

A banking textbook will tell you that banks earn their profits from their net interest margin(difference between rates charged, and rates paid on banks borrowing). Your question makes it clear that the net interest margin math does not add up.

Look at the 10-K (or the 10-Q for that matter) filings for a publicly traded bank that is a significant mortgage originator.

What you'll see in the filings is that the income of the bank is actually driven primarily by fee income. (this fee income is overdraft fees, atm fees, and loan(mortgage) origination fees). For most banks fee income drives 50% or more of their net income. This is how they make money on doing mortgages.

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