The Cash Buffer Test Before You Lock Up Your Money

Opening Scenario

You’re a freelancer who just closed a big project and has six months’ pay sitting in an investment with a multi‑year lockup or hefty annual fees. Two months later your laptop dies, a client delays payment, and a medical bill arrives. You either borrow, sell investments at the worst time, or raid retirement savings you can’t easily replace. That mismatch — having money tied up when you need it — is exactly what the cash‑buffer test is designed to prevent.

What Buffett's Letter Said

Warren Buffett used a decade‑long bet to show a blunt point about fees, liquidity and investor outcomes. Protégé Partners assembled five funds‑of‑funds (and those funds in turn owned interests in many hedge funds). Over the ten‑year stretch through 2016, the five funds‑of‑funds averaged a compounded annual return far below a low‑cost S&P 500 index fund; on $1,000,000 the funds‑of‑funds increase would have been about $220,000 versus about $854,000 for the index fund (Berkshire shareholder letter 2016, p.22). Buffett described the investor results as “dismal — really dismal.” (Berkshire shareholder letter 2016, p.22.) The 2017 update emphasized how layers of fixed and performance fees and broad incentives don’t guarantee better outcomes for investors (Berkshire shareholder letter 2017, p.11).

Note: the shareholder letters discuss Berkshire’s bet and the funds involved; the household application below is a SwitchWize interpretation of those lessons for personal finance.

Why this matters for your household

• Layered fees, lockups, and illiquidity can sharply reduce the effective return on money you thought you were earning. (See 2016 figures, p.22.)
• If you tie up cash that you might need for essentials, you risk selling into market declines or borrowing at high cost — outcomes that compound the drag from fees. (See discussion of fees and incentives, 2017, p.11.)
  So before you lock money away, confirm you have a cash buffer sized to your essential expenses and the stability of your income.

Household example: run the cash‑buffer test (concrete)

Scenario: Dual‑income household. Essential monthly expenses (housing, utilities, groceries, insurance, minimum debt): $4,000. One partner is steady W‑2, the other is freelance.

Step 1 — Baseline buffer calculation

• Essential monthly cost = $4,000.
• Income stability = mixed (one variable earner).
• Editorial guidance buffer target: 6 months × $4,000 = $24,000. (Labelled editorial guidance — see below.)

Step 2 — Investment decision point

• You have $60,000 in savings and plan to invest $40,000 into a fund with a multi‑year lockup or heavy fees.
• Cash‑buffer test: keep at least $24,000 liquid. That leaves $36,000 available to invest without dropping below the buffer; you should not invest more than $36,000 if you want the 6‑month buffer intact.

Alternative example — single‑income, stable W‑2 job: essentials $3,000 → editorial guidance buffer 1–3 months (say 2 months = $6,000), so more investable cash may be available.

What to Do Next

1. List essential monthly expenses (housing, utilities, food, insurance, minimum debt payments).
2. Assess income stability (stable W‑2; mixed; self‑employed/seasonal).
3. Choose a buffer multiple based on income stability (see Editorial guidance).
4. Buffer target = essentials × chosen months.
5. Subtract current liquid cash (checking, savings, short‑term liquid accounts) from the target → your shortfall.
6. Before investing in illiquid or fee‑heavy vehicles, cover that shortfall. If you can’t, hold funds in liquid accounts or scale back the planned investment.
7. Re‑run the test after life changes (job change, new baby, major medical events, starting a business).

Editorial guidance (do not treat as a rule)

• Stable W‑2 income: 1–3 months of essentials (editorial guidance).
• Mixed household income or one variable earner: 3–6 months (editorial guidance).
• Self‑employed, irregular income, or no reliable emergency credit: 6–12 months (editorial guidance).
  These ranges are SwitchWize editorial guidance, not derived from the Berkshire letters.

Rebuilding a buffer after you use it (brief plan)

• Prioritize replenishment as a short‑term goal in your budget.
• Automate regular transfers to a liquid account sized to refill the buffer over a set period (e.g., 3–12 months).
• Temporarily reduce discretionary spending and pause nonessential investing until the buffer is restored.
• If you used retirement accounts, work with a licensed advisor or tax professional on any replacement and tax implications.

Chart/visual brief (what to show and why)
Title: How fees and time‑costs bite returns (two snapshots)

• Data shown as bars for cumulative gain on $1,000,000:
  • Through 2016 (use Buffett’s supplied figures): average funds‑of‑funds gain ≈ $220,000; S&P 500 index fund gain ≈ $854,000 (Berkshire shareholder letter 2016, p.22).
  • Through 2017 (update): cumulative S&P 500 index final gain 125.8% (Berkshire shareholder letter 2017, p.11); funds‑of‑funds results vary in the 2017 table (see p.11).
• Label bars with dollar gains and percent gains; add a caption: “High fees and layers of fees produced much lower investor gains even with expert, incentivized managers.” (2016, p.22; 2017, p.11).
  Alt text: Two bar groups comparing cumulative dollar gains on $1,000,000 for funds‑of‑funds vs S&P index through 2016 and through 2017, showing much higher cumulative gain for the index.

Why I used the 2016 snapshot and noted the 2017 update
The 2016 letter gives the clean dollar comparison through 2016 ($220k vs $854k on $1m), which illustrates fee drag. Berkshire’s 2017 letter provides the updated final results and a deeper discussion of fees and incentives (2017, p.11). Showing both snapshots is transparent: the 2016 view highlights the mid‑bet contrast; the 2017 update confirms the broader point about fee layers and modest investor outcomes.

SwitchWize next step (natural, non‑product)
Today: calculate your essential monthly expenses and pick a buffer multiple that matches your household’s income stability. If you’re short of your target, pause plans to lock up large sums or accept long lockups until the buffer is rebuilt. If you’d like help applying these numbers to your whole financial picture, consult a licensed financial planner or tax professional for personalized advice.

Source note

• Figures and comparison through 2016: Berkshire shareholder letter 2016, p.22.
• Discussion of fee layers, incentives, and the 2017 update: Berkshire shareholder letter 2017, p.11.