The prime bank guarantee scam is a high stakes swindle that was first warned about in 1993. Someone – possibly a good friend or relative – invites you to join a scheme that will make you rich through access to “bank guarantees” which they say can be bought at a discount and sell shortly thereafter at an enormous premium. The likes of pension funds are on stand by, to buy “Prime Bank letters of credit” from large banks. However, the regulations mean that the deals have to go through a middleman. Often the claim is that you’ll make a 20% profit within 30 days.