Proposition 13, adopted by California voters in June 1978, mandates that the Assessor appraise real property based on its value at the time of ownership or new construction.
The factored base year value (FBYV) of real property is either the market value from 1975 or the value established when the property last changed ownership or underwent new construction. This value is then adjusted by an annual inflation factor not to exceed 2% per year.