We do not know exactly how long it takes for your new mortgage to appear on your credit file.
Anecdotally, it seems to take around 3 months to appear.
How does reporting to credit agencies work?
First off, we use the credit rating agency Experian.
On the 10th of each month, we upload the details of all completed loans from the previous month to Experian in a batch. This means for example that on the 10th of August we uploaded a file containing all loan data up to 31st July.
We only report to Experian, but the information is entered into the CAIS database so it's then visible to all other lenders who have access to CAIS.
The data that we report to Experian is not shared with other credit rating agencies.
What is CAIS?
CAIS stands for Credit Account Information Sharing. A CAIS record shows the existence of a credit account.
Virtually every major organisation in the UK that lends to consumers provides information to CAIS on a monthly basis. CAIS is the largest source of information about consumer credit in the UK.