This is a huge commonly held misunderstanding of fractional reserve banking.
'The capital ratio is the percentage of a bank's capital to its risk-weighted assets. Weights are defined by risk-sensitivity ratios whose calculation is dictated under the relevant Accord. Basel II requires that the total capital ratio must be no lower than 8%.'
With $1 billion in deposits a bank may lend upto $12 billion under Basel II assuming a risk weight of 1.0
With $1 billion in assets and $12 billion in liabilities the capital ratio is 8%.
Where does the bank get this extra $11 billion? They borrow it from the Federal Reserve, unless they are lending it to another of their accounts in which case they just credit the account.
There is a disturbing amount of mis-information in this thread. As a sibling commenter writes, deposits have nothing to do with capital.
The Basel regulations are, as the term "risk-weighted assets" which you quoted implies, about the riskiness of assets of the bank.
NB: Loans made by a bank are assets of the bank, and they are risky, that is why Basel regulations are relevant. The corresponding liabilities of the bank are the money that is created in the debtor's accounts when the loan is made. But those liabilities are not part of the Basel computations, because Basel is about risky things. Risks do not come from liabilities, because liabilities are known, certain quantities. Risk only comes from assets.
When a risky asset has to be written off (e.g. loan goes bad), then the asset side of the bank's balance decreases. This is offset by an equal decrease on the liability side of the bank's balance. To be precise, the bank's capital is reduced (yes, capital is a liability).
This makes sense because capital represents the "liability" that the bank has towards its owners. When the bank makes bad decisions, the owners are supposed to pay for it in properly implemented capitalism.
When capital goes below zero, the bank goes bankrupt. Therefore, the ostensible goal of the Basel regulations is to ensure that capital never goes below zero (or, at least, that a lot has to go wrong before that happens).
This is why a risk-weighted sum of the bank's asset (the things that can go bad) is compared to capital (the only liability that can be legitimately decreased).
There's one of two possibilities, either I'm wrong and capital requirements don't work like that, or every bank in the world is insolvent. Given Quantitative easing 1,2,3,etc which do you think is true?
You take the blue pill – the story ends, you wake up in your bed and believe whatever you want to believe. You take the red pill – you stay in Wonderland, and I show you how deep the rabbit hole goes. Remember, all I'm offering is the truth – nothing more.
So from a bank's perspective, a loan is an asset and a deposit is a liability.
Say someone deposits $100 cash (federal reserve notes) into Bank A. Let's say the reserve ratio is 20%. It takes $80 and loans it to someone, who deposits in the same bank. It then takes $64 of that and loans it to someone who deposits in the same bank. It then takes $51 of that and loans it to someone who takes out cash and holds it.
The bank has the following assets: $20 + $16 + $13 in reserve, plus loans of $80 + $64 + $51 = $244.
It has the following liabilities: $100 + $80 + $64 = $244.
Now, if those loans don't get repaid, the bank might not remain solvent, but that has nothing to do with fractional reserve banking. Any entity that is solvent on the books can be rendered insolvent by loans going bad.
The accounting rules for banks are different. They book cashflow differently and I believe balance sheets are presented in a way that essentially neutralises the deposits and loans in order to focus on what the bank itself owns or owes.
'The capital ratio is the percentage of a bank's capital to its risk-weighted assets. Weights are defined by risk-sensitivity ratios whose calculation is dictated under the relevant Accord. Basel II requires that the total capital ratio must be no lower than 8%.'
http://en.wikipedia.org/wiki/Capital_requirement
With $1 billion in deposits a bank may lend upto $12 billion under Basel II assuming a risk weight of 1.0
With $1 billion in assets and $12 billion in liabilities the capital ratio is 8%.
Where does the bank get this extra $11 billion? They borrow it from the Federal Reserve, unless they are lending it to another of their accounts in which case they just credit the account.