The tenant's fractional responsibility for total building operating expenses.
By Angel Campa, Founder · Updated March 2026
The pro rata share is a multiplier applied to every pass-through expense for the entire lease term. A 0.5% error on a building with $1 million in annual operating expenses means $5,000 per year in overcharges. Over a 10-year term, that compounds to $50,000. Verifying that the pro rata share matches the RSF ratio (tenant RSF / building RSF) is one of the highest-value checks in lease abstraction.
Defined in the "Operating Expenses" or "Additional Rent" section. May be stated as a fixed percentage or as a formula (tenant RSF / building total RSF). Cross-reference with the RSF and building RSF figures for verification.
Lextract uses a combination of AWS Textract OCR and Claude AI to identify and extract the pro rata share from your lease PDF. The AI searches for all pages of the document, then assigns a confidence score based on OCR quality and extraction certainty. Fields with lower confidence are flagged for human review.
Lease Structure
The categorization of expense sharing.
Base Year
The foundational year used to calculate operating expense increases in gross leases.
CAM Cap %
The maximum allowable annual increase for controllable operating expenses.
CAM Cap Type
Specifies whether the CAM cap is cumulative and compounding or non-cumulative.
Gross-Up %
The assumed occupancy level used to extrapolate variable operating expenses.
Management Fee Cap
The maximum allowable percentage of gross revenues charged for property management.
Pro rata share equals the tenant's rentable square footage divided by the building's total rentable square footage, expressed as a percentage. For example, a 3,000 RSF tenant in a 60,000 RSF building has a 5.00% pro rata share.
If the building expands or is remeasured, the denominator changes. Some leases fix the pro rata share at signing, while others allow it to float with building RSF changes. A floating share can increase costs if the building adds or loses rentable space.
What accuracy can you realistically expect from AI lease abstraction tools? We break down field-level accuracy rates, where AI excels, where it struggles, and how to validate output.
Compare the top AI lease abstraction tools for commercial real estate in 2026. We review Lextract, Prophia, Kolena, Leasecake, MRI Software, and more — with pricing, accuracy, and use-case guidance.
Free AI lease abstraction tools are fast and easy — but they have real limitations. Here is what free tools deliver, what they miss, and when you need structured output instead.
Upload your lease PDF and Lextract will extract pro rata share along with 98 other structured fields in minutes. Just $20 per lease.
Upload Your Lease