Professional coin grading companies such as NGC and PCGS depend for their survival on maintaining high standards and consistency in authenticating and grading coins. They offer guarantees to back up their opinions. All coins are cross graded by independent experts for the greatest possible accuracy. Every professionally graded coin is sealed in a tamper-evident plastic holder. The holders are known in the industry as "slabs" and the coins referred to as "slabbed." Slabs include a description, a serial number and a guaranteed grade.

Professionally graded coins offer collectors and investors the security of a guarantee of that coins are both genuine and fairly graded. Market value shifts dramatically with grade. The difference between coins graded MS-63 and MS-65 can represent thousands of dollars in market value. Even though there are strict standards on which experts agree, coin grading remains is a subjective process. Smart investors and collectors will study coin grading and look at as many coins as possible to be able to determine for themselves the quality of the coins they want to own.