Why can two reserve studies of the same property disagree?

Fannie Mae requires a reserve study to address specific subjects but does not require a standard format or prescribe every component life, cost input, or assumption. Two studies can therefore differ because their inventories, condition findings, timing, costs, balances, or funding assumptions differ.

Compare the inputs before the totals

Put the studies side by side and compare:

• which major components are included;
• condition and remaining useful life;
• quantities, scope, and repair-versus-replacement assumptions;
• cost date and documented cost basis;
• opening reserve balance and its date;
• inflation and other financial assumptions;
• recommended annual contributions; and
• the stated funding plan.

The current Fannie Mae source requires those subject areas but leaves professional judgment within them. A different total is not enough to prove which study is current or supportable.

What changes the lender question?

If a lender uses the study instead of the reserve-allocation budget calculation, the budget must include the study's highest recommended allocation and baseline funding cannot carry the substitution. A disagreement between studies can therefore affect which recommendation is being tested, but the lender still decides the complete eligibility question.

Sources

• Fannie Mae Selling Guide B4-2.2-01, Full Review Process, version August 5, 2026 — no required standard format; required reserve-study subjects.

Primary source accessed September 11, 2026.