"Selling" a debt may not remove liability for repaying it
Borrowers have been warned to ignore misleading adverts which suggest people can get rid of their debts or loans simply by selling them.
The Office of Fair Trading (OFT) says there has been a surge in these adverts from debt and claims management companies.
But it says debts cannot legally be sold without a lender's permission.
Some companies offering this "service" are now going to be prosecuted or closed down.
"You cannot simply sell on your debt and its liabilities, and businesses that make misleading claims to the contrary are just trying to take advantage of consumers' distress," said Ray Watson, the OFT's director of credit.
"The OFT will not hesitate to take swift action against businesses which deliberately mislead consumers," he added.
The OFT said the sort of firms it was concerned about typically charged their victims a £350 "administration fee" and a further 10% to 20% of the debt as a "transfer fee".
It said so-called "brokers", who matched clients to debt or claims management companies, with a view to selling or buying their loans, were also misleading their customers.
It pointed out that even if a "sale" takes place, the original borrower will still be legally responsible for repaying the loan, as well as losing any money they may have paid as part of the deal.
Borrowers can also still be chased by debt collection agencies and bailiffs, and have their credit scores damaged, the OFT warned.
This is just the latest spate of misleading adverts being made by debt and claims management companies trying to cash in on peoples' worries about their debts.
In the past few months the OFT, Ministry of Justice and Solicitors Regulation Authority (SRA) have all warned firms not to make misleading claims suggesting that credit card and bank debts, agreed before April 2007, may be challenged because of a supposed loop-hole in the law.
Last week a claims management website called Loan-Free was told by the Advertising Standards Authority (ASA) not to repeat such adverts.