What is a “Proposition 8” value?

From time to time, the market value of a property on January 1 may have fallen below the Prop 13 adjusted base year value. In this situation the Assessor has the authority to reduce the assessed value to the current market value as of January 1. This is sometimes referred to as a “Proposition 8” assessment, after the November 1978 proposition that amended Article XIII A to allow these reductions in value.