Yes, this is none of our business, they make a profit from lending money that people save to the bank,
no they dont
bank loans PRINT NEW MONEY
to explain more simply
imagine a bank has 10,000,000 customers saving an average balance of $25k each
that balance STAYS in customers accounts (total $250,000,000,000)
however banks
separately get to
create an allotment of ~ $225b(90%) fresh money limit it can give out to credit/mortgage applicants
they dont hand out depositors savings.. they dont hand out this fresh money total per year. either
they have to balance it out.
instead they can only send out a certain amount per year to keep the separate total balanced and equitable compared to the pegged depositors balance that allow this separate total to be made
EG for mortgage applicants that want 15 year mortgages, then out of the $225b pegged reserve, a bank can only offer $15b total per year. this allows banks to offer upto $15b a year each year without exceeding the total pegged reserve new money balance they create
by this its allows for mortgage payers to make their payments per year to refill that allotment over the years whereby at the 15th year the total back into the reserve is back to the $225b (plus more for interest and other fee's the bank get to keep)
the money used in loans is the banks own creation.. based on a pegged rate of its depositors average total holdings
banks do require bank customer deposits to then be able have the separate fresh money pot. but its not the depositors own funds that get taken out of accounts and given out as loans.. its like a secondary pot of fresh print. that goes out but must come in as repayments to cancel out the print that was created
EG
imagine your wife has $100 in her hand. and laws allow you to create a new $90 bank note to loan out as long as that someone repays $99 in X time for you to then balance your creation and allow you to then loan out again your creation.
EG
if 10 people want a loan of 10 year repayment (1 person per year) they can only get a loan max of $9 each where by the 10th year the total should return the $90 total(plus fees, interest the banks get to keep)
you are not using your wifes $100 to give as loans. but her existence of having $100 allows you to create $90 under safeguards and loan conditions that you hope the repayments rebalance the books of your $90 creation when the loan term completes, for you to then loan out your creation balance that pegs to your wifes holdings