NatWest customers are most likely to be targeted by spam and fraudulent "phishing" emails, claims a company that specialises in providing anti-spam software.
Based on its own efforts to prevent its customers falling victim to fraudsters, ClearMyMail has come up with a hit-list of 10 financial services companies being impersonated by fraudsters.
Some 41 per cent of all phishing emails blocked by ClearMyMail were aimed at NatWest, with fraudsters sending out fake emails, based on genuine communications from the bank, including logos and corporate colours.
Citibank came in second, targeted in 27 per cent of scams of this type, followed by HSBC (11 per cent), Abbey (6 per cent), Lloyds TSB (4 per cent), PayPal (the online banking service for the likes of eBay – 2 per cent), Royal Bank of Scotland (1 per cent), Nationwide (1 per cent), Halifax (0.8 per cent) and MBNA (0.5 per cent).
"Without any email protection, UK online banking customers are at severe risk of being tricked into giving away their account details to criminal gangs," said Dan Field of ClearMyMail. "The phishing emails are very well constructed and often look exactly like a legitimate bank message."
A spokesperson for NatWest said: "We continue to take fraud extremely seriously. We have developed and put in place significant security processes and resources to protect against this type of threat. Phishing is an industry-wide issue and this research is a snapshot that doesn't reflect that the focus on different organisations fluctuates greatly.
"NatWest has taken considerable steps to warn customers against responding to phishing emails, and continues to clearly advise that we will never ask for this type of personal information to be provided by email."