Flux / Variance Analysis

Month-end variance commentary against prior period and budget. Run in the Excel add-in when the TB lives in a workbook, or Cowork when the TB is exported.

Required inputs

• Current period TB — current month or YTD trial balance with account number, account name, balance.
• Prior period TB — same format. Same account list, ideally — if accounts differ, the skill flags new/missing accounts.
• Budget — same format. Period-matched (current period budget for monthly flux, YTD budget for YTD flux).
• Period identifier — e.g., 2026-04 (month) or 2026-Q1 (quarter).
• Optional: prior commentary — prior period's flux workpaper. Used to check whether explanations are recurring (a recurring variance with the same explanation may be a pattern, not noise).

Workflow

1. Load and validate. Read all three TBs. Run scripts/compute_variances.py which:

- Joins on account number. - Computes varpmdollar, varpmpct, varbuddollar, varbudpct. - Flags accounts that appear in current but not prior, or in prior but not current. - Excludes accounts whose absolute current and prior balances are both below materiality.fluxdeminimis_dollar.

1. Apply materiality. From firm-config/references/materiality.md, load fluxthresholddollar and fluxthresholdpct. An account triggers commentary if either threshold is exceeded on either comparison (prior period or budget). The skill works on the filtered set; smaller variances are listed but not commented.

1. Detect anomalies. Run scripts/anomaly_detect.py:

- Sign change — balance flipped from debit to credit or vice versa - New account — exists in current, not in prior - Missing account — exists in prior, not in current (balance went to zero with no posting) - Recurring variance — same direction material variance N months in a row (materiality.fluxanomalyrecurring_months) - Budget miss — current actuals are >2x budget or <0.5x budget

1. Classify each material variance. Pick one:

- TIMING — variance explained by a period cutoff (e.g., invoice posted to wrong month) - RECLASS — variance explained by a known reclassification with a referenced JE - BUSINESSDRIVER — variance explained by an identified operational change with a source - LIKELYERROR — variance pattern matches a known error mode (sign flip, decimal slip, account swap) - UNKNOWN — no supported explanation → generates a preparer question

1. Draft commentary, only when a source supports it. Acceptable sources:

- A specific JE in the current period (cite JE_ID) - A specific accrual or reclass (cite reference) - A prior-period explanation that explicitly stated this pattern would continue - An operational fact in inputs the user provided (headcount change, new contract)

If no source supports an explanation, the skill does not draft one. It generates a question for the account owner. "Probably driven by Q1 marketing push" is not a commentary — it is a guess.

1. Generate preparer questions for UNKNOWN items. One question per account, specific:

- Bad: "Please explain the variance." - Good: "Account 6200 Marketing-Advertising shows $42K above budget (+38%) for April. Prior period was on budget. What drove the increase — was there a campaign launch or a reclass from another period?"

1. Output workbook tabs:

- Cover — period, comparison basis, status - SourceTBCurrent, SourceTBPrior, SourceBudget — raw inputs - Variances — sortable table: account, balances, $ var, % var, materiality flag, classification, commentary, question - Anomalies — sign changes, new/missing accounts, recurring patterns - Questions — preparer questions consolidated for follow-up - Summary — high-level commentary: largest favorable, largest unfavorable, themes - Evidence — sources for each commentary line - ReviewNotes

Invariants

• Never draft a business explanation without an identifiable source. "I don't have enough information to explain this variance" is a valid output and preferred over speculation.
• A UNKNOWN classification must always have a corresponding preparer question.
• Recurring identical explanations ("timing — December accrual" for the same account 4 months running) are a smell, not a comfort. Flag as LIKELYERROR or MANUALREVIEW_REQUIRED.

When to say "I don't know"

• Account list doesn't align between current/prior/budget → stop and ask whether there was a chart change.
• Budget is missing for >20% of material accounts → produce flux against prior period only and note the budget gap.
• Prior commentary references things not in inputs → don't invent context; flag for follow-up.