Devon, Somerset and Torbay Trading Standards is issuing a warning for people to be aware of a spate of investment scams.
The Trading Standards service has received a number of complaints from people who have fallen for the scams, which claimed a high level of return for a minimal risk.
In fact, victims typically lost tens of thousands of pounds.
Trading Standards wants people to know that there are many types of investment scams to look out for, and that scams are continuously evolving.
Someone could be asked to invest in unusual products, such as carbon credits, bitcoin, or plots of land. Or they could be asked to become a member of a pyramid scheme, invest in offshore schemes, or to trade in binary options.
"There are things that people can do to avoid falling for a scam," says Steve Gardiner, Interventions Manager, Devon, Somerset and Torbay Trading Standards.
"Ask yourself, was the offer unsolicited and is the offer and company legitimate? Don't provide any financial or personal information before establishing whether the company's legitimate.
"Do you fully understand how the investment works? And ask for confirmation in writing before committing to it.
"Don't be pressured into making a decision. Take your time.
"And of course, is it too good to be true?"
Companies can only offer financial products and services if they're properly authorised, registered and/or approved, unless they're specifically exempt from doing so.
The Financial Conduct Authority publishes a warning list of companies known to scam people, at www.fca.org.uk/scamsmart. Legitimate companies should also be listed on the financial services register, at https://register.fca.org.uk
Other checks include carrying out a "who is" search on the internet, which can identify who and where a website is registered.
Companies are often based outside the UK. If they're based within Europe, consumer advice can be obtained from European Consumer Centre, tel: 01268 886690.
Complaints can be reported to Trading Standards on 03454 040506, and to Action Fraud (the UK's national fraud and cyber crime reporting centre) on 0300 1232040
Mr Gardiner said, "These pernicious and persistent approaches are designed to steal your money or your personal information.
"Always remember, if an offer sounds like it's too good to be true, bear in mind that it probably is."