Finance & Treasury · Finance, Risk & Compliance
Should you build or buy Lease Accounting Subledger (ASC 842 / IFRS 16)?
Lease accounting subledger software calculates right-of-use asset amortization and lease liability schedules under ASC 842 or IFRS 16, handles modification accounting and remeasurements, generates the journal entries required for each reporting period, and produces the footnote disclosures that auditors and financial statement users require.
The build-vs-buy decision for Lease Accounting Subledger (ASC 842 / IFRS 16) turns on whether the calculation logic is sufficiently standard to make vendor solutions genuinely interchangeable versus whether lease portfolio complexity justifies owning the engine; the calculus has been stable because ASC 842 defines the math and audit requirements make vendor output the path of least resistance.
Build it, buy it, or bridge?
When building makes sense
Building a lease accounting subledger is theoretically possible since the calculation logic is algorithmic and well-documented. ASC 842 defines the incremental borrowing rate application, ROU asset amortization schedule, and lease liability roll-forward precisely. For a company with a handful of simple leases and no external audit requirement, a spreadsheet or custom script could work. The problem is that modification accounting — when lease terms change, when options are exercised, when remeasurement triggers occur — adds combinatorial complexity that grows with portfolio size. Beyond a handful of leases, the edge cases in modification accounting and the GL posting logic required to produce footnote-ready disclosure schedules make self-build increasingly impractical. The audit requirement is the final gate: external auditors expect a recognized system with a documented methodology and a reproducible audit trail. Self-built subledgers rarely pass that bar. The only credible internal build case is for companies with very small, stable lease portfolios operating outside of external audit requirements.
When buying makes sense
Buying a lease accounting subledger is the standard approach for any company with a meaningful lease portfolio under ASC 842 or IFRS 16. Platforms like LeaseQuery, Visual Lease, and Trullion handle the full calculation lifecycle: incremental borrowing rate application, ROU asset amortization, lease liability schedules, modification accounting, and the journal entry generation that ties to the GL. They produce the footnote disclosure schedules auditors expect, formatted to the standard and with the audit trail that makes year-end review efficient. The pricing scales with lease count, and the vendor economics make sense because the alternative — building modification accounting logic robust enough for an external auditor — is not a worthwhile use of internal engineering resources. Lease accounting is compliance infrastructure. The software decision should be about which vendor's data migration tooling, ERP integration, and disclosure output format best matches the existing accounting environment.
The desk read
ASC 842 and IFRS 16 subledger logic is almost entirely standard-defined. The incremental borrowing rate application, ROU asset amortization, lease liability schedules, and modification accounting all follow prescribed GAAP and IFRS rules that are the same for every company. Platforms like LeaseQuery, Visual Lease, and Trullion are carrying the GL integration depth and audit trail that makes those outputs auditor-ready, not proprietary calculation logic.
The build case exists in principle, since the math is algorithmic and documented. In practice, modification accounting for large portfolios, variable payment modeling, and the GL integration required to produce footnote-ready disclosures make self-builds theoretical for companies with more than a handful of leases. Lease accounting software is an accounting compliance utility, and the vendor economics reflect that: pricing scales with lease count, audit requirements make vendor outputs the path of least resistance, and there's no competitive advantage available from doing this differently.
Frequently asked
What is a Lease Accounting Subledger (ASC 842 / IFRS 16)?
Lease accounting subledger software calculates right-of-use asset amortization and lease liability schedules under ASC 842 or IFRS 16, handles modification accounting and remeasurements, generates the journal entries required for each reporting period, and produces the footnote disclosures that auditors and financial statement users require.
When does building a Lease Accounting Subledger (ASC 842 / IFRS 16) make sense?
Building is only realistic for companies with a very small number of simple leases and no external audit requirement. Modification accounting complexity and auditor acceptance requirements make self-builds impractical for companies with meaningful lease portfolios.
When does buying a Lease Accounting Subledger (ASC 842 / IFRS 16) make sense?
Buying makes sense for any company with real lease obligations under ASC 842 or IFRS 16. Vendors like LeaseQuery and Visual Lease handle modification accounting, GL posting, and auditor-ready disclosure output that self-builds cannot match on any practical timeline.
What are the main Lease Accounting Subledger (ASC 842 / IFRS 16) vendors?
Representative vendors include LeaseQuery (FinQuery), Visual Lease, IRIS Innervision, Trullion. B4 Pro scores the full set.