joellewis/liquidity-management

Liquidity Management

Core Concepts

Cash Flow Forecasting

Project income and expenses monthly for 12+ months:

• Income sources: salary, business income, investment income, rental income, side gigs
• Fixed expenses: mortgage/rent, insurance, subscriptions, loan payments
• Variable expenses: food, utilities, discretionary spending
• Periodic lumpy expenses: property taxes, insurance premiums, tuition, estimated taxes
• Net cash flow: income - expenses per period → identifies surplus/deficit months

Income Smoothing (Variable Earners)

For commission, freelance, seasonal, or bonus-heavy income:

• Compute trailing 12-month average income as "base salary equivalent"
• Budget based on base amount, not peak months
• Buffer surplus months into a smoothing reserve (separate from emergency fund)
• Target smoothing reserve: 2-3 months of base expenses
• Draw from reserve in below-average months

Liquidity Tiers

Classify investable assets by time to access:

| Tier | Access Time | Examples | Typical Yield | |------|------------|---------|---------------| | Tier 1 — Immediate | Same day | Checking and savings at your primary bank, money market funds | Low | | Tier 2 — Short-term | 1-3 business days | High-yield savings at an online bank, brokerage sweep cash, T-bills, bond funds and bond ETFs | Moderate | | Tier 3 — Medium-term | 1-4 weeks (or penalty cost) | CDs (early-withdrawal penalty), I-bonds (after 1-year lockup) | Moderate-High | | Tier 4 — Long-term | 30+ days | Real estate, PE/VC, locked alternatives, retirement accounts (pre-59½) | Highest |

Tier notes:

• Tier 1 vs Tier 2 savings: the distinction is transfer time, not product type. A savings account at your primary bank offers same-day access (Tier 1); a high-yield savings account at an online bank typically requires a 1-3 business day ACH transfer to reach your checking account (Tier 2).
• Bond funds and bond ETFs: both settle T+1 (the US moved to T+1 settlement in May 2024 for equities, ETFs, and mutual funds), so sale proceeds are available in roughly 1-3 business days including transfer to a bank. They belong in Tier 2 for access time — though, unlike deposits, the sale price is subject to market risk.

CD Laddering

Stagger CD maturities for regular access + higher yields:

• Example: $60K split into 6 CDs maturing every 2 months
• As each CD matures: either use the cash or reinvest at the longest rung
• Benefit: captures term premium while maintaining periodic liquidity
• Variant: 3/6/9/12-month ladder, renewing each at 12 months

Bond Laddering

Similar concept with Treasury or corporate bonds:

• Annual maturities across 1-5 or 1-10 years
• Provides predictable cash flows and interest rate diversification
• Rungs mature and are reinvested at prevailing rates (automatic rate averaging)

T-Bill Ladder

Short-duration, high-liquidity ladder:

• 4/8/13/26-week T-bills rolling continuously
• Purchased at Treasury Direct or through brokerage
• State tax exempt (federal only)
• Highly liquid: can sell on secondary market before maturity

Liquidity Metrics

• Liquidity ratio: liquid assets / monthly expenses (target ≥ 3-6)
• Cash reserve ratio: cash + near-cash / total portfolio
• Current ratio (business): current assets / current liabilities (target > 1.5)
• Quick ratio (business): (current assets - inventory) / current liabilities

Seasonal and Tax Planning

• Estimated taxes: quarterly for self-employed (Q1: Apr 15, Q2: Jun 15, Q3: Sep 15, Q4: Jan 15)
• Property taxes: typically semi-annual — reserve monthly for escrow-like smoothing
• Holiday/vacation: set aside monthly into dedicated sub-account
• Annual expenses: insurance premiums, memberships → amortize monthly

Margin of Safety

Maintain buffer above minimum liquidity requirements:

• Income uncertainty → larger buffer
• Known upcoming large expenses → pre-fund 2-3 months early
• Market correlation: income and portfolio may both decline in recession

Key Formulas

| Formula | Expression | Use Case | |---------|-----------|----------| | Liquidity ratio | Liquid assets / monthly expenses | Adequacy check | | Net cash flow | Σ income - Σ expenses | Monthly surplus/deficit | | CD ladder yield | Weighted average of rung yields | Blended return on ladder | | Smoothing reserve | Base monthly expenses × 2-3 | Buffer for variable income | | Breakeven penalty | CD early withdrawal penalty / (CD rate - savings rate) | Whether to break CD |

Worked Examples

Example 1: CD Ladder Construction

Given: $60,000 to deploy, want liquidity every 2 months, 12-month CDs yielding 4.8% Calculate: Ladder structure and blended yield Solution:

• Split into 6 equal CDs of $10,000 each
• Stagger maturities: 2, 4, 6, 8, 10, 12 months
• Initial yields may vary by term: 2mo=4.2%, 4mo=4.4%, 6mo=4.5%, 8mo=4.6%, 10mo=4.7%, 12mo=4.8%
• Blended yield ≈ average = 4.53%
• Every 2 months one CD matures → reinvest at 12-month rate (4.8%) or use funds
• After full cycle (12 months), all CDs are 12-month earning 4.8%

Example 2: Variable Income Smoothing

Given: Freelancer with monthly income ranging $3,000-$15,000, average $8,000. Monthly expenses $5,500. Calculate: Base budget and smoothing reserve target Solution:

• Base budget: $5,500/month (essential expenses)
• Average monthly surplus: $8,000 - $5,500 = $2,500
• Smoothing reserve target: $5,500 × 3 = $16,500
• In months earning >$8K: direct excess to smoothing reserve until funded
• In months earning <$5.5K: draw from smoothing reserve
• Once reserve is funded, excess above $8K goes to savings/investment goals

Common Pitfalls

• Illiquidity surprise: needing cash when assets are locked in alternatives or retirement accounts
• Penalty drag from breaking CDs frequently (defeats the purpose of laddering)
• Over-optimizing yield at the expense of access (yield chasing in illiquid instruments)
• Not planning for estimated tax payments (large quarterly cash needs for self-employed)
• Ignoring correlation between income loss and market decline (both happen in recessions)
• Treating credit lines as liquidity (they can be revoked when most needed)

Cross-References

• emergency-fund (wealth-management plugin, Layer 6): first tier of liquidity, must be funded before optimizing
• lending (wealth-management plugin, Layer 6): margin loans, HELOCs as backup liquidity (with risks)
• time-value-of-money (core plugin, Layer 0): CD/bond pricing, yield calculations
• debt-management (wealth-management plugin, Layer 6): debt payments are fixed cash flow obligations
• savings-goals (wealth-management plugin, Layer 6): multiple goals compete for available cash flow
• tax-efficiency (wealth-management plugin, Layer 5): estimated taxes, tax-loss harvesting timing
• fixed-income-sovereign (wealth-management plugin, Layer 2): T-bill ladder mechanics, Treasury Direct
• financial-planning-workflow (advisory-practice plugin, Layer 10): cash flow tier structure informs the liquidity analysis in comprehensive financial plans

Running the script

Run the reference implementation directly:

uv run scripts/liquidity_management.py     # PEP 723 header resolves dependencies automatically
python3 scripts/liquidity_management.py    # after: pip install numpy scipy

A bare run prints a demo covering liquidity ratios, a 12-month cash flow projection, cash runway, liquidity tier analysis, CD ladder construction, income smoothing, and CD breakeven analysis. Use --verify to recompute the demo figures and assert they match this skill's worked examples (prints PASS/FAIL, exits nonzero on mismatch), and --help to list the available classes and functions. The file is primarily meant to be imported as a module (from liquidity_management import LiquidityManagement) rather than run standalone.