If you own a top level domain e.g. .com, .net or .biz you may receive an official looking letter from the Domain Renewal Group.
This is a scam that skirts around the edges of the law. They purposefully make it look like a bill or urgent renewal letter. However if you read it carefully (particularly the tiny print on the back) you will be paying well above the market price to transfer your domain away from your current registrar.