thirteen-week-cash-flow（十三周现金流量）

13-Week Cash Flow Forecast Skill

The 13-week cash flow (13WCF) is the operating room monitor of finance — it tells you exactly how much oxygen (cash) you have left, week by week. This skill builds, maintains, and analyzes 13WCFs for any business size.

When to Use This Skill

Trigger phrases:

• "Build a 13-week cash flow"
• "How's our short-term liquidity?"
• "Lender is asking for a weekly cash forecast"
• "We need to manage cash tightly"
• "Board wants a cash dashboard"
• "Are we going to make payroll next month?"
• "We're in a cash crunch — model it out"
• "Variance analysis on our cash forecast"

NOT for:

• Annual budget models → use a full 3-statement model or startup-financial-model
• Long-range (12-36 month) forecasts → use startup-financial-model
• Tax cash planning → requires tax-specific skill
• Real-time bank data syncing → connect to banking/QBO APIs
• Accounts payable automation → use invoice-automation or qbo-automation
• Cap table or equity cash modeling → use cap-table-manager

Why 13 Weeks?

The 13-week horizon (one quarter) is the standard because:

• Lenders require it during credit facility draws and covenant testing
• Distressed situations demand weekly visibility, not monthly guesses
• Payroll, rent, and debt service are predictable within this window
• AR/AP cycles (30-60-90 day terms) fully play out in 13 weeks
• Operationally actionable — you can actually influence week 2-8 outcomes

Model Structure

Two Approaches

1. Direct Method (Preferred for Distress / Tight Liquidity) Track actual cash in and cash out at the bank — receipts and disbursements. Most accurate for near-term. Does not reconcile to GAAP net income.

2. Indirect Method (For Stable Businesses) Start from P&L and adjust for non-cash items and working capital changes. Better for businesses with predictable accrual-to-cash conversion.

For most 13WCF use cases, use the direct method.

Direct Method Structure

BEGINNING CASH BALANCE
─────────────────────
CASH RECEIPTS:
  + Customer Payments / Collections (AR)
  + Cash Sales
  + Other Receipts (grants, tax refunds, asset sales)
  = Total Cash Receipts

CASH DISBURSEMENTS:
  - Payroll & Payroll Taxes
  - Accounts Payable (vendor payments)
  - Rent / Lease Payments
  - Debt Service (principal + interest)
  - Utilities & Operating Costs
  - Insurance Premiums
  - Tax Payments (estimated quarterly, payroll taxes)
  - Capital Expenditures
  - Other Disbursements
  = Total Cash Disbursements

NET CASH FLOW = Total Receipts - Total Disbursements

ENDING CASH BALANCE = Beginning Cash + Net Cash Flow
─────────────────────────────────────────────────────
CREDIT FACILITY:
  Beginning Revolver Balance
  + Draws
  - Repayments
  = Ending Revolver Balance

LIQUIDITY:
  Available Cash (Ending Balance)
  + Available Revolver Capacity
  = Total Liquidity

Week-by-Week Build Process

Step 1: Anchor on Opening Balance

Pull the actual bank balance as of the forecast start date.
Use cleared balance, not book balance (reconcile first).
Note: include all accounts (operating, payroll, reserve).

Step 2: Build Collections Forecast (AR Receipts)

The hardest part — converting AR to cash by week:

AR Aging as of today:
  0-30 days: $X → collect at [DSO-adjusted timing]
  31-60 days: $X → collect with risk haircut
  61-90 days: $X → apply collection probability %
  90+ days: $X → apply risk factor (often 50-70% discount)

Collection Timing Model:
  Invoice Date | Invoice Amount | Expected Pay Date | Week # | Amount

For recurring customers:
  Track historical pay timing (e.g., customer pays net 45 on average)
  Apply that pattern forward to open invoices

For new sales / pipeline:
  Week of billing + customer payment terms = collection week

Collections Spreadsheet Template:

Customer | Invoice # | Invoice Date | Due Date | Amount | Probability | Expected Week | Forecasted Receipt
---------|-----------|--------------|----------|--------|-------------|---------------|-------------------
Acme     | INV-1042  | 2026-03-01   | 3/31     | 5,000  | 95%         | Week 3        | 4,750
Beta Co  | INV-1041  | 2026-02-15   | 3/17     | 12,000 | 100%        | Week 1        | 12,000
...

Step 3: Build Disbursements Schedule

Map every known outflow to a specific week:

Fixed/Recurring (easy to schedule):

Payroll:         Week 2, 4, 6, 8, 10, 12 (bi-weekly example)
Rent:            Week 1 (1st of month)
Debt service:    Week X (per loan schedule)
Insurance:       Week X (monthly or quarterly)
Software subs:   Week X (auto-billing dates)

Variable (AP-driven):

Vendor payments = AP aging + payment terms + cash position management
  - Which vendors can be stretched? (net 45 → pay net 60)
  - Which have early pay discounts? (2/10 net 30)
  - Which are critical suppliers (must pay on time)?

AP Payment Priority Stack:
  Tier 1 (pay on time, always): Payroll, payroll taxes, critical vendors
  Tier 2 (pay per terms): Standard trade payables
  Tier 3 (stretch if needed): Non-critical, relationship-based payables

One-Time / Lumpy:

Tax payments: quarterly estimated taxes (dates known)
CapEx:        per purchase order / contract milestone
Legal:        per retainer or invoice

Step 4: Assemble the 13 Weeks

          | Wk 1 | Wk 2 | Wk 3 | Wk 4 | Wk 5 | ... | Wk 13
          |------|------|------|------|------|-----|------
Beg Cash  |  500 |  420 |  385 |  610 |  540 | ... |   X
Receipts  |  200 |  350 |  400 |  180 |  290 | ... |   X
Disbursem | (280)| (385)| (175)| (250)| (310)| ... |  (X)
Net Flow  |  (80)| (35) |  225 |  (70)|  (20)| ... |   X
End Cash  |  420 |  385 |  610 |  540 |  520 | ... |   X

Step 5: Revolver / Credit Line Integration

If the company has a revolver or line of credit:

  Minimum cash cushion target: $X (covenant or management decision)
  
  Draw logic:
    If Ending Cash < Minimum → Draw from revolver to cover gap
    If Ending Cash > Minimum + buffer → Repay revolver
  
  Revolver capacity check:
    Borrowing base = AR eligible × advance rate (typically 80%)
    Available = Borrowing Base - Outstanding Balance
    
  Week-by-week:
    Ending Cash (pre-revolver) + Draw - Repayment = Ending Cash (post-revolver)

Variance Analysis

The 13WCF is only useful if you track actuals vs. forecast weekly.

Weekly Variance Report Format

Week [X] Variance Analysis — [Date]

RECEIPTS:
  Forecast: $XXX,XXX
  Actual:   $XXX,XXX
  Variance: $X,XXX [F/U] — [explanation]

DISBURSEMENTS:
  Forecast: $XXX,XXX
  Actual:   $XXX,XXX
  Variance: $X,XXX [F/U] — [explanation]

ENDING CASH:
  Forecast: $XXX,XXX
  Actual:   $XXX,XXX
  Variance: $X,XXX [F/U]

KEY VARIANCES:
  1. Collections short $15k — Beta Co delayed payment to next week (confirmed)
  2. Payroll $2k under — headcount timing (one hire pushed to Week 8)
  3. AP $8k over — emergency HVAC repair not in forecast

ROLL-FORWARD NOTE:
  Beta Co $15k pushed to Week [Y]
  Revolver draw increased by $10k to maintain minimum

F = Favorable (more cash), U = Unfavorable (less cash)

Trend Signals to Watch

🔴 RED FLAGS:
  - Ending cash below minimum 2+ consecutive weeks
  - Collections consistently 20%+ below forecast
  - Revolver utilization increasing each week (borrowing to fund operations)
  - Weeks where disbursements exceed receipts by >50%

🟡 YELLOW FLAGS:
  - Single-week collection shortfall (customer timing issue)
  - Forecast accuracy below 85% for 2+ weeks
  - Growing AP balance (stretching payables unsustainably)

🟢 GREEN:
  - Forecast accuracy >90%
  - Ending cash growing week-over-week
  - Revolver balance declining

Lender / Investor Reporting Package

When submitting 13WCF to lenders, include:

Cover Memo:
  - Period covered (13 weeks from X to Y)
  - Opening cash balance (reconciled)
  - Key assumptions (collection timing, payroll dates, AP strategy)
  - Liquidity summary: lowest cash point, when, and amount
  - Borrowing base availability
  - Covenant compliance status

Exhibits:
  1. 13WCF Model (week-by-week table)
  2. AR Aging and Collections Detail
  3. AP Aging and Payment Schedule
  4. Borrowing Base Certificate (if applicable)
  5. Week-over-week variance summary (if rolling update)

Covenant Monitoring

Many credit facilities include liquidity covenants. Track weekly:

Common Covenants:
  Minimum Liquidity:     Cash + Available Revolver ≥ $X
  Minimum Cash Balance:  Bank balance ≥ $X at week end
  Springing Covenant:    Triggers additional restrictions if cash < $X
  
Covenant Dashboard:
  Covenant            | Threshold | Current | Headroom | Status
  -------------------|-----------|---------|----------|--------
  Min Liquidity       | $500k     | $620k   | $120k    | ✅ Pass
  Min Cash            | $200k     | $385k   | $185k    | ✅ Pass
  Revolver Usage      | ≤85%      | 62%     | 23%      | ✅ Pass
  
Early Warning: Flag when headroom < 25% of threshold

Structured JSON Output

When producing 13WCF output for export or integration:

{
  "forecast_meta": {
    "company": "Acme Corp",
    "start_date": "2026-03-16",
    "end_date": "2026-06-07",
    "currency": "USD",
    "opening_cash": 420000,
    "method": "direct",
    "generated": "2026-03-16"
  },
  "weeks": [
    {
      "week_num": 1,
      "week_start": "2026-03-16",
      "week_end": "2026-03-22",
      "beginning_cash": 420000,
      "receipts": {
        "ar_collections": 180000,
        "cash_sales": 15000,
        "other": 0,
        "total": 195000
      },
      "disbursements": {
        "payroll": 0,
        "accounts_payable": 85000,
        "rent": 22000,
        "debt_service": 0,
        "taxes": 0,
        "other": 12000,
        "total": 119000
      },
      "net_cash_flow": 76000,
      "ending_cash_pre_revolver": 496000,
      "revolver_draw": 0,
      "revolver_repayment": 50000,
      "ending_cash": 446000,
      "revolver_balance": 200000,
      "total_liquidity": 846000,
      "covenant_min_liquidity": 500000,
      "covenant_headroom": 346000,
      "covenant_status": "pass"
    }
  ],
  "summary": {
    "lowest_cash_week": 4,
    "lowest_cash_amount": 285000,
    "total_receipts_13wk": 2100000,
    "total_disbursements_13wk": 1850000,
    "ending_cash_week13": 670000,
    "max_revolver_balance": 350000,
    "forecast_accuracy_target": 0.90
  }
}

Step-by-Step Workflow

When a user asks for a 13WCF:

Step 1: Intake

□ Opening bank balance (as of today, cleared)
□ AR aging report (all open invoices)
□ AP aging report (all open payables)
□ Payroll schedule (dates and amounts)
□ Loan schedule (debt service dates)
□ Known large one-time items (rent, tax payments, CapEx)
□ Credit facility details (limit, outstanding, borrowing base)
□ Minimum cash threshold (management target or covenant)
□ Any known collection risks (disputed invoices, slow customers)

Step 2: Build Collections

• Map each AR invoice to expected collection week
• Apply probability haircuts for aging invoices
• Add new sales pipeline if known

Step 3: Build Disbursement Schedule

• Fixed: map every recurring payment to exact week
• Variable: apply AP aging + payment priority to determine pay weeks
• One-time: calendar all known lumpy items

Step 4: Assemble Model

• Week-by-week table: beginning cash → receipts → disbursements → ending cash
• Add revolver mechanics if applicable
• Calculate total liquidity and covenant positions

Step 5: Stress Test

• What if collections are 20% lower than forecast?
• What if a large customer (>15% of receipts) delays 2 weeks?
• What if payroll increases 10% (bonus, new hire)?
• Identify the "cliff" week — when does cash hit the minimum?

Step 6: Management Actions

Based on the forecast, identify levers:

If cash tight in Week 3-4:
  - Accelerate collections: offer 2% early pay discount
  - Stretch AP Tier 2 vendors by 2 weeks
  - Draw $50k from revolver
  - Defer non-critical CapEx

If cash comfortable:
  - Repay revolver to reduce interest
  - Build minimum cash cushion
  - Pre-pay Tier 1 vendors for relationship / discount

Step 7: Deliver

• Formatted weekly table
• Variance actuals block (if rolling update)
• Covenant dashboard
• Top 3 risks and management actions

Example Usage

User: "We need a 13-week cash flow. We have $380k in the bank, $210k in AR (mostly net 30), payroll of $85k bi-weekly, rent $18k first of month, and a $500k revolver at 60% drawn. Minimum cash covenant is $150k."

Sam's response:

13-Week Cash Flow — Starting Week of 3/16/2026
Opening Cash: $380,000 | Revolver: $300k drawn / $200k available | Covenant: $150k minimum

QUICK SNAPSHOT:
  Lowest cash point: Week 3 (pre-payroll week) at ~$195k — $45k above covenant
  Revolver: Recommend drawing $50k at Week 3 to build cushion to $245k
  Collections: $210k AR should convert ~$180k over weeks 1-4 (net 30 timing)

WEEKLY SUMMARY:
  Wk 1: Beg $380k | Receipts $95k | Disb ($88k) | End $387k
  Wk 2: Beg $387k | Receipts $60k | Disb ($108k) | End $339k  ← payroll + rent
  Wk 3: Beg $339k | Receipts $85k | Disb ($90k)  | End $334k
  Wk 4: Beg $334k | Receipts $55k | Disb ($108k) | End $281k  ← payroll + rent
  ...
  Wk 13: Projected ending ~$310k | Revolver same or better

KEY RISKS:
  1. If top customer (accounts for ~$80k AR) delays 2 weeks → Week 4 cash drops to ~$195k, barely above covenant
  2. Any unexpected >$30k expense in weeks 2-4 hits covenant
  
RECOMMENDED ACTIONS:
  - Call top AR customer now — confirm payment timing
  - Pre-approve $75k revolver draw to trigger if needed (don't draw yet)
  - Hold AP Tier 2 payments in weeks 2-4 until AR clears

Want me to build out all 13 weeks in full detail with the complete disbursement schedule?

Integration Points

• startup-financial-model — Long-range context for the 13WCF (is the business structurally viable?)
• kpi-alert-system — Set automated alerts when ending cash < covenant + $50k buffer
• qbo-automation — Pull AR/AP aging and bank balances directly from QuickBooks
• ar-collections-agent — Coordinate with collections workflow to improve receipt timing
• report-generator — Format 13WCF into lender-ready PDF package

Reference: Key Formulas

Net Cash Flow         = Total Receipts - Total Disbursements
Ending Cash           = Beginning Cash + Net Cash Flow ± Revolver Activity
Total Liquidity       = Ending Cash + Available Revolver Capacity
Covenant Headroom     = Total Liquidity - Covenant Minimum
Borrowing Base        = Eligible AR × Advance Rate (typically 80%)
Available Revolver    = Borrowing Base - Outstanding Balance
Collection Efficiency = Actual Collections / Forecasted Collections × 100
DSO (Days Sales Out.) = AR Balance / (Revenue / 90 days)
DPO (Days Pay. Out.)  = AP Balance / (COGS / 90 days)
Cash Conversion Cycle = DSO + DIO - DPO