That is according to a new report published today (12 December) by the Financial Services Authority (FSA), which has attributed the financier's struggles to six main factors, including deficiencies in regulation.
Within the document, the body indicated that the lender struggled because of significant weaknesses in its capital position caused by bad decisions from senior officials.
It is noted that the inadequacies of the global regulatory framework permitted this to happen, while the bank - which has total assets in excess of Â£1,000 billion ($1,555 billion) was also overly-reliant on short-term wholesale funding.
Adair Turner, chairman of the FSA, observed: "Banks across the world, including RBS, were operating on levels of capital and liquidity that were far too low. These prudential regulations have been changed radically since the crisis."
By Asim Shah