Institutions are obliged to tell savers when they change their rates. Normally, they do this through notices in branches, or adverts in the press.
Last year, the Banking Code was changed to require banks and building societies to write to savers with money in obsolete accounts and tell them about newer accounts on offer. But the code does not require savings institutions to tell customers who have accounts that are still available about better options.
The picture is almost as complex for those looking for credit cards and personal loans, often with low introductory interest rates to persuade them to switch.
Helping the public to find the best deal is the philosophy behind Moneynet, an internet service that independently compiles listings of interest rates for savers and borrowers. The service started last year with mortgages - it now has data from 97 lenders - and it has just expanded its site to add personal loans, credit cards and savings accounts.
Moneynet has more than 1,600 mortgage products on its site. Thirty-four companies provide personal loan information, and 90 offer details of savings rates. The site is updated daily, and although it is up to the providers to supply up-to-date information, Moneynet says it chases any it has not heard from after a few weeks.
Moneynet does not charge financial services companies for listings. Instead, it relies on advertising to fund the site.
The service offers an instructive lesson in the value of shopping around. A hundred pounds placed in an instant access account will pay as little as 0.5 per cent, or more than 7 per cent. With personal loans, the best interest rate is 9.90 per cent and the worst, 19.9 per cent, based on pounds 5,000 loaned over five years. The gap between a cheap and an expensive credit card is even greater: the lowest-cost issuer charges 13.9 per cent (permanent rate) and the dearest charges 24.9 per cent.
Moneynet offers direct links through to lenders' websites, so it is possible to use the service as a one-stop shop. The company is also thinking about adding on-line application forms, and it is working on a new database for off-shore accounts, an area where interest rates can change daily.
Links: moneynet: http://www. moneynet.co.uk
Stephen Pritchard can be contacted at hi-tech-investor@dial. pipex.com