One of the features of housing bubbles is overvaluation of homes as mortgage collateral. Normally it is assumed that loan-to-value doesn't exceed 80%. With an inflated value, a loan-to-value of 120% (where the mortgage covers even legal, administrative, tax and even physical customization costs of the purchase) can be turned into an 80% "book" loan to value. So, jack up the regulatory capital requirements by 75%.

Economics is politics by other means