A more thorough explanation:

Grantor-grantee index is a tool used by most counties in the United States to record the transferring of property ownership. It is an official documentation of land transfers, and courts look to these indexes to see who owns property.

Every time someone sells their land, they or the loan company should record the sale with the county records office. Before someone even pays for a piece of property, a title search should be conducted where a title company looks through a grantor-grantee index to find the ownership status of the property the individual wishes to buy. Otherwise, a person may be purchasing an invalid title, which could result in them paying for no legal ownership at all.

Historically, grantor-grantee indexes have been in a physical form with transfers grouped by year and by name so that transfers can be properly researched. In recent years, these indexes have become digital and organized in a variety of ways.

For example, if John sells his house to Jane, the sale should be recorded in the grantor-grantee index. If Jane wants to sell the house to someone else, the new buyer's title company will look at the grantor-grantee index to make sure that Jane is the legal owner of the property and has the right to sell it.

The grantor-grantee index is an essential tool for anyone involved in real estate transactions. If you purchase property but it is not inserted into the index, another person could purchase the same property and record it with the county, likely leaving your purchase invalid.