Massachusetts Commercial Late Fees: Default Interest and Enforcement

The famous Massachusetts 30-day late fee grace period that applies to residential tenancies under MGL Ch. 186, §15B does NOT apply to commercial leases. Commercial late fees are governed entirely by the terms of the lease agreement.

Disclaimer: This guide provides general legal information for educational purposes only and does not constitute legal advice. Commercial contract enforcement is complex. Always consult a qualified attorney. Information last verified: March 2026.

No Statutory Grace Period for Commercial

Because §15B's 30-day grace period is exclusive to residential tenancies, a commercial landlord can legally charge a late fee on the very first day rent is overdue, provided the lease authorizes it. If the lease says rent is due on the 1st and a $500 late fee accrues on the 2nd, that is generally enforceable.

Default Interest vs. Flat Fees

Massachusetts commercial leases typically employ one of two mechanisms for penalizing late payments:

1. Default Interest

The lease imposes daily interest on any unpaid rent from the due date until payment is received.

• Typical Rate: 10-18% per annum, or a percentage above the Prime Rate (e.g., "Prime + 5%").
• Enforceability: While Massachusetts courts give more deference to commercial contracts than residential ones, an excessively high interest rate (e.g., 36% per annum) could be challenged as an unenforceable "penalty" under general contract law principles.

2. Flat Late Fee

A fixed dollar amount (e.g., $500) or a percentage of the monthly rent (e.g., 5%) charged if rent is not received after a short grace period (e.g., 5 or 10 days).

• The fee must bear a reasonable relationship to the landlord's actual damages from the delayed payment (administrative costs, financing costs).

Combining Both Mechanisms

It is common to see both mechanisms in the same lease: a flat late fee triggered after a short grace period, plus default interest running from the due date on any amounts remaining unpaid after, e.g., 30 days.

Interaction with Eviction

A landlord can simultaneously charge late fees/interest and begin eviction proceedings. The two remedies are not mutually exclusive.

• If the lease is clear, lost rent, late fees, and default interest can all be pursued in the Summary Process action or a subsequent breach of contract suit.

How Landager Helps

Landager's commercial ledger is configured to apply the exact late fee structure defined in each individual Massachusetts lease—whether it's a flat fee, default interest above Prime, or both. Our system ensures that late charges are calculated accurately and documented for use in any future Summary Process filing.

Back to Massachusetts Commercial Lease Laws Overview.