The regulatory crackdown on home lending practices is continuing to inspire behavioural changes at major banks, with the country's largest mortgage lender announcing another overhaul of credit standards and procedures.Under sweeping changes announced yesterday to mortgage aggregators, Commonwealth Bank will require all third-party originators of its home loan products to improve disclosure about the financial position of prospective borrowers.Mortgage brokers will be expected to furnish granular information about their clients' product relationships with other lenders.From next Monday, brokers will need to collect account numbers on credit cards, personal loans and home finance products that a prospective home loan client holds with other lenders.CBA is also cracking down on loan applicants who report their main source of personal income is rental revenue.Brokers will no longer be allowed to submit rental appraisals on behalf of clients. Instead, CBA is demanding income statements from real estate agents, copies of lease agreements, independent valuation reports, taxation returns and bank statements showing three months of rental credits into an account.The bank is clamping down on questionable practices that previously enabled brokers to inflate the disposable income of loan applicants.Under the new assessment criteria, the bank will not allow borrowers to artificially inflate their assessable income by adding non-cash related income, such as fringe benefits.CBA revealed in the notification to brokers that it previously allowed applicants to add a notional amount of A$5000 to their gross income if they had a fully maintained company motor vehicle.Other changes are likely to make it harder for young borrowers to secure a home loan. Some loan applicants who live rent-free will be required to include a notional amount of $650 per month in their cost of living estimates."These changes will help ensure that we continue to meet our regulatory and responsible lending requirements," the bank told brokers in the notification.In a sign that the Australian Prudential Regulation Authority is intensifying its micro-management of lending standards, CBA said was also tightening its credit policies in specific suburbs and regions where property prices are under pressure and non-performing loans are increasing.While the bank did not identify the suburbs and regions affected, it said it was lowering maximum loan-to-value ratios without lender's mortgage insurance from 80 per cent to 70 per cent in "selected postcodes".CBA also revealed that certain postcodes would be subject to mortgage insurance "loadings" from next week.The bank will also prevent borrowers from deploying negative gearing strategies on certain types of mortgage properties - presumably apartments - in selected postcodes.