Module 2 · Market Instruments · Lesson 6

Debt

A tool or a trap, depending on the hand that holds it.

Debt is the most misunderstood number on a balance sheet. Investors who do not understand it tend either to fear it irrationally or ignore it entirely — both of which lead to losses. A company with the right amount of debt is more profitable, more efficient, and faster-growing than one with none. A company with too much debt is one bad quarter away from disaster.

Debt is simply money the company has borrowed from banks, bond investors, or other lenders. In exchange, the company pays interest at a fixed or floating rate and must repay the principal at a future date. The borrowed funds let the business build factories, acquire competitors, or fund product development without diluting existing shareholders by issuing new stock. Used wisely, debt amplifies returns. Used recklessly, it amplifies losses.

The difference between a healthy debt load and a fatal one is rarely obvious in good times. It becomes obvious in bad times — and by then it is too late. This lesson covers the five debt metrics that separate solvent companies from precarious ones, the most famous case study in financial history (Lehman Brothers), and the rules Warren Buffett uses to dodge companies that look fine until they suddenly are not.

The same balance sheet looks completely different depending on what the borrowed money is doing. Apple holds tens of billions in debt because borrowing at 3 percent and earning 25 percent on the deployed capital is one of the best trades on Earth. A struggling retailer holding the same debt is one bad season from default. The number alone tells you almost nothing without context.

Part One

Beginner visual framework

Simple explanation

The idea in plain English

Debt can help a company grow, but too much debt reduces flexibility. The key question is whether the company can comfortably service its obligations in bad times.

Worked example

How this looks in real investing

A stable utility may handle more debt than a cyclical retailer because its cash flows are more predictable.

Common beginner mistake

What to avoid

Assuming all debt is bad or all debt is harmless. The quality of cash flow matters.

Action step

Do this before moving on

Check debt, interest expense and cash on hand before judging a company as safe.

Quick checkpoint

Can you explain it simply? If not, slow down and reread the visual framework.

Can you apply it? Use the worked example as a template with a real company or fund.

Can you avoid the trap? The common mistake is the part most beginners overlook.

The five debt metrics that matter

Hundreds of debt-related figures appear on a balance sheet. Five tell you everything that matters.

01

Debt-to-Equity Ratio How leveraged is the balance sheet? Formula. D/E = Total Debt ÷ Shareholders’ Equity. A D/E of 0.5 means $0.50 of debt for every $1 of owner capital. Under 0.5 is conservative; 0.5 to 1.0 is normal for most industries; over 2.0 starts to feel risky outside of banks and utilities. Buffett’s rule. He prefers companies with debt under 20 percent of equity (D/E < 0.2). Higher ratios are acceptable only for specific industries — utilities, banks — where stable cash flows justify the leverage.

02

Interest Coverage Ratio How many times can earnings cover the interest bill? Formula. Interest Coverage = EBIT ÷ Interest Expense. EBIT is earnings before interest and tax. A coverage ratio of 8 means earnings could cover the interest bill eight times over — comfortable. A ratio under 2 means the business is one bad quarter from missing payments. Rule of thumb. Above 4× is healthy. Between 2× and 4× requires watching. Below 2× is a red flag. Falling coverage ratios — even from a high base — signal the leverage is creeping toward unsustainable.

03

Current Ratio & Quick Ratio Can the company pay its short-term bills? Formulas. Current Ratio = Current Assets ÷ Current Liabilities. Quick Ratio = (Current Assets − Inventory) ÷ Current Liabilities. Both measure short-term solvency — whether the company can cover what it owes in the next twelve months without selling long-term assets. Rule of thumb. Current Ratio above 1.5 is healthy. Quick Ratio above 1.0 is healthy. A Quick Ratio under 1.0 means the company depends on selling inventory or borrowing further to meet near-term obligations — a fragile position when credit tightens.

04

Debt Maturity Profile When does the bill come due? What it shows. The 10-K lists when each debt tranche matures. A company with $10 billion in debt all maturing next year faces a refinancing risk that a company with the same $10 billion spread evenly over ten years does not. What to watch. If a company has a large debt maturity in the next 12–24 months and credit markets are tight, they may be forced to refinance at much higher rates, or sell assets at unfavourable prices. A “debt wall” can sink an otherwise solvent business in a credit crunch.

05

Credit Rating What the rating agencies say about default risk. What it is. Moody’s, S&P, and Fitch assess the likelihood a company will repay its debt. Ratings run from AAA (highest quality) down through BBB (still investment-grade) to BB and below (“junk”). The lower the rating, the higher the interest rate the company must pay. What to watch. Investment-grade (BBB and above) is generally safe territory. Below BBB carries materially higher default risk. A recent downgrade matters as much as the absolute level — it signals deteriorating fundamentals and often comes before, not after, a stock decline.

Part Two

Case study: Lehman Brothers, September 2008

The most famous debt-driven collapse in modern history offers the clearest lesson on leverage. Lehman Brothers had survived 158 years — wars, depressions, multiple recessions. It died in 48 hours because of one number: 31 to 1.

Part Three

How to evaluate any company’s debt in 10 minutes

Five quick checks. Every one is in the public filings.

One. Find total debt on the balance sheet. Add “Short-term debt” and “Long-term debt” (sometimes called “Borrowings”). Some companies also have operating lease liabilities — include those if they are material.

Two. Calculate the Debt-to-Equity ratio. Total debt ÷ Shareholders’ equity. Under 0.5 is conservative. 0.5–1.0 is normal. Over 2.0 is aggressive unless it is a financial institution or utility.

Three. Check interest coverage. EBIT ÷ Interest expense from the income statement. Above 4× is healthy. Below 2× is a red flag, even if everything else looks fine.

Four. Look at the debt maturity schedule. In the 10-K, find the table showing when debt principal repayments are due. A large maturity in the next 24 months is a refinancing risk. Spread maturities are safer than lumpy ones.

Five. Compare to industry peers. A 1.5× D/E ratio is high for a software company and normal for an industrial. Use the company’s competitors as the relevant baseline, not absolute thresholds.

Part Four

Where investors misread debt

Even careful investors get burned. Five recurring patterns.

Treating all debt as bad. Companies with zero debt may be inefficient. Capital structure has an optimal point — debt at low cost can dramatically improve return on equity. Reject a company because of too much debt; don’t reject one just because it has some.

Ignoring off-balance-sheet liabilities. Operating leases, pension obligations, and guarantees of subsidiaries often sit outside the headline debt number. A retailer with $5 billion in reported debt and $20 billion in operating lease commitments is closer to $25 billion in real debt. Read the footnotes.

Confusing low rates today with low rates forever. Companies that borrowed cheaply during the 2010s look fine on current interest coverage. Those same debts must eventually be refinanced — possibly at much higher rates. Project what the interest bill will look like if rates rise 3 percentage points.

Mistake	Why It Hurts	Defence
Debt phobia	Reject good companies on principle	Look at coverage, not just absolute debt
Ignoring off-B/S liabilities	Real leverage hidden in notes	Always read footnotes
Assuming rates stay low	Surprise interest bills	Stress-test against +3% rates
Trusting “manageable”	Manageable in good times only	Stress-test against recession
Margin loans personally	Personal leverage amplifies losses	Avoid investing on borrowed money

Trusting company descriptions of “manageable” debt. Every CFO calls the current debt level “manageable” until the day they file for bankruptcy. Make your own assessment from the numbers; never rely on management’s adjective.

Using personal margin loans to invest. The same warning applies to your own balance sheet. Borrowing to invest amplifies returns in good markets and amplifies wipeouts in bad ones. Most retail investors who use margin in their first decade lose materially more than non-margin investors over the same period. The math of leverage is symmetric, but the psychology of forced selling at a margin call is not.

Investor Wisdom

What the great investors said about leverage

Ten quotes on borrowed money — the most powerful, most dangerous tool in finance.

Beginner visual framework

Key Takeaways

Six things to take from this lesson

01	Debt is a tool, not inherently good or bad. The same level can be healthy for one company and fatal for another.
02	Five metrics matter: D/E ratio, interest coverage, current/quick ratios, debt maturity profile, credit rating.
03	Buffett rejects companies with debt over 20% of equity or repayment longer than 2 years of net profit.
04	Lehman Brothers’ 31:1 leverage made a 3.6% asset drop a fatal event. Hidden leverage kills.
05	Off-balance-sheet liabilities, debt maturity walls, and rising-rate scenarios are where most surprises hide.
06	Personally, avoid margin loans. Compounding does the work; leverage adds risk that compounding cannot heal.

Five Commitments

What you commit to before moving on

Read each one. If you cannot honestly commit to it, the lesson is not finished.

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End of Lesson

Module 2 . Lesson 6 of 21 . Continue to Lesson 7 . Compound Interest.