Aberdeen Asset Management is warning people to look out for emails from fraudsters purporting to be from the company.
The investment management group, which manages £193 billion worth of institutional and private investors' money, is currently Moneywise's investment trust group of the year.
Its alert warns that it has become aware of an individual offering "false lease agreements" through email using the name and old logo of Aberdeen Asset Management.
The individual is also using a profile on Linkedin, which suggests he is an Aberdeen Asset Management member of staff to lend credibility to his approach.
But the firm states: "Aberdeen does not offer such agreements and will never contact the public in this way to offer such.
"Although our staff will use Linkedin for networking purposes they never make contact with prospective clients or offer unsolicited business proposals via the site."
It says if you are in any doubt as to the veracity of a person purporting to work for Aberdeen, do not offer any personal information. Instead, you should contact its investor services centre listed on its website at aberdeen-asset.co.uk.
The firm has also warned about cold callers, again purporting to be from Aberdeen, offering people investment in company shares. The callers do not work for Aberdeen and any third party making such offers has no link with the company.
Action Fraud says these could be boiler room scams, where a payment from you is required to release the supposed payment for your shares; or they could be a simple attempt to gain your personal information with which to commit identity fraud.
To report a fraud and receive a police crime reference number, call Action Fraud on 0300 123 2040 or use its online fraud reporting tool at actionfraud.police.uk.