You just acquired 2,000 units. The deal closed, the champagne happened, and now someone asks: how do we get their data into our system?
This is the question that ruins the first six months of every acquisition. Not because the technology is hard — the tools exist — but because nobody prepares for what the data actually looks like once you open the box.
What You Expect
Clean tenant records, consistent GL codes, standardized lease structures, complete vendor files. A data export that maps neatly into your existing system with a few field adjustments.
What You Get
Three years of decisions made by people who no longer work there, encoded in a database that reflects how the previous management company operated, not how you operate. Specifically:
- Their chart of accounts is not your chart of accounts. They tracked expenses in categories that do not map to yours. Their "maintenance" includes things you split into three separate line items. Merging without reclassifying means your portfolio-level reporting will be wrong for every period that includes the acquired properties.
- Their vendor records duplicate yours. The same landscaping company that services your existing properties also services the acquired ones — under a different name, different tax ID format, sometimes a different entity entirely. If you import without deduplication, you now have two records for the same vendor. Your AP team will discover this when they cut two checks for the same invoice.
- Their lease structures use different conventions. Security deposit handling, late fee calculations, utility billing methods, CAM reconciliation schedules — all slightly different from yours. These are not fields you can bulk-update. Each one requires a decision about how to normalize without losing the historical record.
- Their historical data has the same quality issues yours does, plus theirs. Every data quality problem they had — and did not fix — is now your data quality problem. Duplicate tenants, inconsistent unit types, overwritten move-in dates, orphaned charge codes. All of it migrates with the data.
The Six-Month Tax
Companies that do not plan for data migration spend the first six months after an acquisition fighting their reporting. Month-end closes take twice as long because the new properties do not reconcile cleanly. Owner reports require manual adjustments because the chart of accounts does not match. Variance analysis is meaningless because you are comparing apples to the previous company's oranges.
This is not a technology problem. The system works fine. The data is what does not work.
The cost is real: two to four hours of additional accounting time per property per month for the first six months while someone manually reconciles what the migration did not fix. At 2,000 units across 10 properties, that is 20 to 40 hours per month of avoidable work. At fully loaded accounting rates, you are spending $1,500 to $3,000 per month cleaning up a migration that should have been done correctly once.
What a Good Migration Actually Looks Like
Before the data moves:
- Map their chart of accounts to yours. Identify every code that does not have a direct match. Decide — in advance — how each one will be reclassified. Document the mapping so your accounting team can explain every historical reclassification.
- Run a vendor deduplication against your existing records. Identify overlaps. Decide which record survives and which gets merged. Do this before import, not after.
- Audit their lease structures for convention differences. Flag the ones that need normalization and the ones that can import as-is.
- Pull a data quality report on their system before migration. Duplicate tenants, missing fields, inconsistent unit types, expired leases still showing active. Fix what you can on their side first. It is cheaper to clean data in the source system than to clean it after migration.
During migration:
- Migrate in stages, not all at once. Bring over one property, validate the reporting, confirm the chart of accounts maps correctly, verify the vendor records merged as expected. Then do the rest. The time you lose to staging you gain back in not having to fix ten properties simultaneously.
- Preserve the audit trail. Every reclassification, every merge, every field normalization should be documented. Your auditors will ask. Your owners will ask. Have the answer ready.
After migration:
- Run parallel reporting for at least one month-end close. Compare the new system's output against the old system's output for the same period. Differences are either legitimate reclassifications (which you can explain) or errors (which you need to fix before they compound).
The Acquisition Due Diligence Gap
Most acquisition due diligence evaluates the financials, the physical condition, the market, and the legal structure. Almost none of it evaluates the data. How clean are the records? How consistent is the chart of accounts? How many data quality issues will migrate with the portfolio?
Adding a data quality assessment to your acquisition due diligence does not change whether you do the deal. It changes how you budget for the integration. A $500 data audit during due diligence can prevent $20,000 in post-close cleanup. That is a return most investors would take.