Supplementary assessment is an assessment added to the municipal assessment roll during the year to capture property value changes from new construction, renovations, or property changes occurring after the annual assessment date. Without supplementary assessment, new buildings would not be taxed until the following year's regular assessment. Supplementary assessments allow municipalities to collect taxes on increased property values sooner, capturing revenue from development during the same year construction completes. Property owners receive supplementary tax bills reflecting the added assessment, typically pro-rated for the portion of the year remaining. Supplementary assessment processes vary by province but generally involve periodic identification of completed construction, valuation by assessors, and issuance of supplementary tax notices.