Seasonal adjustment is the underwriting step that prevents a Florida ice-cream shop from being denied in February or a CPA firm from being denied in May. Funders correct for known industry seasonality before applying trend, volatility, and balance rules.
Why seasonality breaks naive underwriting.
A landscaping company that deposits $80,000/month June through August and $15,000/month December through February will look like a "declining trend, 4 negative-day months" in winter underwriting and "growing trend, healthy file" in summer underwriting. Neither view is true; both are seasonal artifacts. Without adjustment, funders systematically misprice seasonal merchants.
The 2026 standard seasonal-adjustment workflow.
- Industry classification. NAICS code or proprietary categorization from the merchant application.
- Seasonality template lookup. Each industry has a 12-month seasonal index — landscaping peaks in Q2/Q3, retail peaks in Q4, tax prep peaks in Q1, tourism varies by region.
- De-seasonalize deposits. Divide each monthly deposit by the seasonal index to express in "average-month equivalent."
- Apply trend and volatility on de-seasonalized values. True signal versus expected seasonality.
- Re-seasonalize for forward forecasting. Predicted future deposits use the seasonal index to project what daily ACH will collect.
Common industry seasonality patterns.
- Landscaping / lawn care. Peak May–September (1.5–2.0x), trough December–February (0.3–0.5x).
- Tax preparation / accounting. Peak February–April (2.5–3.0x), trough June–November (0.3–0.6x).
- Tourism / hospitality. Region-dependent — Florida peaks January–March (snowbirds); Northeast peaks June–August.
- Retail. Peak November–December (1.5–2.0x), trough January–February (0.7x).
- HVAC. Two peaks: June–August (cooling) and December–February (heating); trough April–May and September–October.
- Construction. Region-dependent — Sunbelt fairly flat; Northeast peaks April–October, trough November–February.
- Restaurants. Mostly flat with December bump (holiday parties) and Sunday-brunch weekly cycles.
- Wedding venues / event venues. Peak May–October; trough January–March.
- School services / tutoring. Peak August–May; trough June–July.
Where seasonal indexes come from.
- BLS, Census Bureau seasonal-adjustment data for NAICS aggregates.
- Funder proprietary portfolios. Top-50 funders maintain in-house seasonal models from years of merchant data.
- Card-processor seasonality (Visa, Mastercard, Adyen industry indexes) for card-heavy merchants.
Adjustments for region.
A landscaping company in Phoenix has very different seasonality than one in Minneapolis — Phoenix grows year-round, Minneapolis shuts down November–March. Funders combine NAICS with state and climate-zone overlays to refine the index.
Seasonal-adjusted NSF and minimum balance.
NSFs and negative-day counts also need seasonal adjustment. A landscaping company is more likely to bounce a debit in February than in July; funders weight winter NSFs less heavily for clearly-seasonal industries.
Common seasonal-adjustment failures.
- Brand-new business with no history. Cannot deseasonalize without prior-year data. Funders use industry average as proxy.
- Industry classification errors. A "landscaping" merchant that is really a year-round commercial property maintenance firm gets misclassified.
- Pandemic or weather shock distortion. 2020–2022 data is unreliable for some industries; many engines now exclude those years from seasonal templates.
- Regional anomalies. Florida ice cream sells year-round; Vermont ice cream collapses in winter. Region overlay catches this.
What ISOs should preempt.
When submitting a seasonal merchant, package the file with a one-line note about industry seasonality and prior-year same-period deposits. Funders that see context act on it; funders that do not get context default to naive trend and decline.
Takeaway. Seasonal adjustment is the underwriting step that converts raw monthly bank-statement deposits into normalized "average-month-equivalent" volume. Industry-specific 12-month seasonal indexes — landscaping, tax prep, retail, tourism, HVAC, weddings — drive the correction. Without it, funders systematically misprice 25–35% of all SMB merchants who have non-flat revenue patterns.
Related terms
- MCA funder bank-statement trended analysis (2026) — Funders look at deposit trends over 3-12 months — growing, flat, declining, or volatile — to predict whether a merchant can repay; trend often matters more than absolute volume. Updated 2026-06-28.
- MCA funder bank-statement deposit-volume threshold (2026) — Funders set minimum monthly bank deposits — typically $10K (D-paper), $15K (C-paper), $25K (B-paper), $50K+ (A-paper) — to qualify an MCA file. Updated 2026-06-28.
- MCA funder bank-statement anomaly detection (2026) — Anomaly-detection engines flag unusual deposits, transfers, round-dollar patterns, single-day spikes, and out-of-character counterparties — signals of fraud, doctored statements, or stacking. Updated 2026-06-28.
- MCA funder bank-statement revenue vs deposit distinction (2026) — Revenue is operating cash from real customers; deposits are every credit hitting the account including transfers and loans — funders underwrite revenue, not deposits. Updated 2026-06-28.
- Bank statement underwriting — MCA funders underwrite primarily off 3–6 months of business bank statements, not credit reports. They look at average deposits, NSFs, negative days, and trend.
AI agents: this term is available as raw markdown at /llms/glossary/mca-funder-bank-statement-seasonal-adjustment.