What Degree of Financial Leverage Measures
A company’s fixed financing charges do not usually change when its operating income changes. Interest must still be paid, for example, even when EBIT falls. As a result, a given percentage change in EBIT can produce a larger percentage change in earnings available to common shareholders. Degree of financial leverage (DFL) measures that sensitivity at a specified operating level.
The phrase “at a specified operating level” matters. DFL is a point measure: it depends on the EBIT being considered as well as the company’s financing charges. It is not generally one permanent number for a company, and it does not by itself describe the likelihood of any particular change in EBIT.
For a company with debt but no preferred shares, the standard formula is \(DFL=EBIT/(EBIT-I)\), where \(I\) is fixed interest expense. The formula applies when the company has positive common earnings, faces a constant tax rate on taxable income, and can use the assumed tax treatment consistently. Preferred dividends require an adjustment, developed below.
Deriving the Formula
Let \(T\) be a constant tax rate and \(D_P\) be fixed preferred dividends. Assume interest is deductible, preferred dividends are paid from after-tax earnings, and the tax benefit or expense changes proportionally with EBIT. Under these assumptions, earnings available to common shareholders are:
The key reason DFL has its familiar form is that an increase in EBIT does not change fixed interest or preferred dividends. It changes taxable income dollar for dollar, so common earnings change by the after-tax amount of that increase. The resulting elasticity follows directly.
With \(I\), \(D_P\), and \(T\) held constant, \(dE_C/dEBIT=1-T\).
Multiply the change in common earnings per dollar of EBIT by the ratio of EBIT to common earnings: \(DFL=(1-T)EBIT/E_C\).
Since \(E_C=(EBIT-I)(1-T)-D_P\), divide numerator and denominator by \(1-T\) to obtain the equivalent formula below.
If there are no preferred dividends, set \(D_P=0\). The factor \(1-T\) then cancels, giving \(DFL=EBIT/(EBIT-I)\). This cancellation does not mean taxes have no effect on the dollar amount of common earnings; it means that, under the stated constant-tax assumptions, the after-tax change and after-tax earnings have the same tax factor.
The denominator in the adjusted formula includes preferred dividends expressed as a pre-tax equivalent. Preferred dividends are not tax-deductible, so a company must earn \(D_P/(1-T)\) before tax to have \(D_P\) available after tax. If there are multiple kinds of fixed financing charges or a different tax treatment, use the underlying common-earnings equation rather than applying a memorized formula without checking its assumptions.
Worked Calculations
Worked Example: Debt Financing and the Tax Cancellation
A hypothetical company has annual EBIT of $600,000, fixed annual interest expense of $120,000, and a constant 25% tax rate. It has no preferred shares. Calculate DFL at this EBIT. State the method and identify a common calculation error.
Method and assumptions. Use the point-elasticity definition, with interest fixed, taxes at 25%, and no preferred dividends. Common earnings are net income because there are no preferred dividends.
First calculate earnings before tax: \(600{,}000-120{,}000=\$480{,}000\). Taxes are \(0.25(480{,}000)=\$120{,}000\), so common earnings are \(480{,}000-120{,}000=\$360{,}000\).
An additional dollar of EBIT adds \(1-0.25=0.75\) dollars to common earnings. Thus:
The debt-only shortcut gives the same result: \(600{,}000/(600{,}000-120{,}000)=600{,}000/480{,}000=1.25\). As a check, the shortcut agrees with the elasticity calculation based on the actual after-tax common earnings.
Common mistake avoided. Using \(600{,}000/360{,}000=1.6667\) omits the after-tax change in earnings. The numerator of the elasticity calculation must include the marginal change \(dE_C/dEBIT=0.75\). The corrected DFL is 1.25, not 1.6667.
Worked Example: Including Preferred Dividends
A hypothetical firm reports annual EBIT of $500,000. It pays $80,000 of fixed interest and $60,000 of fixed preferred dividends. Its tax rate is a constant 25%, and the tax treatment is as assumed in the formula. Calculate DFL at this EBIT.
Method and assumptions. Calculate earnings available to common shareholders, then use their marginal response to EBIT in the point-elasticity definition. Interest and preferred dividends are fixed.
Earnings before tax are \(500{,}000-80{,}000=\$420{,}000\). Taxes are \(0.25(420{,}000)=\$105{,}000\). Net income is \(420{,}000-105{,}000=\$315{,}000\), and common earnings after preferred dividends are \(315{,}000-60{,}000=\$255{,}000\).
Each additional dollar of EBIT increases common earnings by \(1-0.25=0.75\) dollars, so:
Check using the adjusted formula: the pre-tax equivalent of the preferred dividend is \(60{,}000/0.75=\$80{,}000\). Therefore \(DFL=500{,}000/(500{,}000-80{,}000-80{,}000)=500{,}000/340{,}000\approx1.4706\). The two methods agree.
Common mistake avoided. Preferred dividends cannot be treated as if they were tax-deductible interest. Subtracting only $60,000 in a pre-tax denominator would understate the fixed-charge burden. The correct pre-tax equivalent is $80,000.
Worked Example: DFL Near the Fixed-Charge Break-Even Level
A hypothetical business has annual EBIT of $210,000, fixed interest of $200,000, no preferred shares, and a constant 25% tax rate. Calculate common earnings and DFL at this EBIT. Explain what the result indicates.
Method and assumptions. Use the debt-only formula and verify it using the elasticity definition. The tax rate is constant and interest is fixed.
Earnings before tax are \(210{,}000-200{,}000=\$10{,}000\). Taxes are \(0.25(10{,}000)=\$2{,}500\), leaving common earnings of \(10{,}000-2{,}500=\$7{,}500\). The debt-only formula gives:
For the check, an additional dollar of EBIT adds $0.75 to common earnings. The point elasticity is \(0.75(210{,}000/7{,}500)=157{,}500/7{,}500=21\), as before.
Interpretation. At the stated point, the local percentage sensitivity of common earnings is 21 times the percentage sensitivity of EBIT. This high value occurs because earnings after interest are small relative to EBIT. It is not a guarantee that a finite EBIT change will produce exactly 21 times that percentage change.
Common mistake avoided. A large DFL does not mean EBIT itself is unusually large or that the company will necessarily earn a particular amount. It signals sensitivity around the stated operating level, given the fixed financing charges and assumptions.
Interpreting the Measure Correctly
When common earnings and EBIT are positive, DFL is typically greater than one if fixed financing charges are present. With no interest and no preferred dividends, \(E_C=EBIT(1-T)\), so \(DFL=1\): a percentage change in EBIT produces the same local percentage change in common earnings under the model. Fixed charges reduce the residual earnings base without changing the marginal after-tax response to EBIT, which is why DFL increases as that residual base shrinks.
DFL is a local measure. It describes a small percentage change around the EBIT used to calculate it. For a finite change, the exact percentage change in common earnings should be calculated from the earnings equation at the new EBIT; a point elasticity is not generally an exact multiplier for a large change.
The usual positive-earnings interpretation also has a boundary. If EBIT equals the fixed-charge break-even level, common earnings are zero and the percentage change relative to common earnings is undefined. If earnings are negative, the algebraic derivative may still be calculated, but a percentage change relative to a negative earnings base can be misleading. In either case, report the underlying earnings amounts and explain the limitation rather than presenting DFL as an ordinary positive sensitivity multiple.
The standard formula also needs care when taxes are not proportional to EBIT, tax losses cannot be used immediately, interest is variable, or other charges change with operating income. In those cases, the marginal change in common earnings may not equal \(1-T\). Start from the relevant earnings relationship, determine its derivative at the stated EBIT, and then form the elasticity only if common earnings are a suitable nonzero base.
Common Exam Traps
- Using the wrong earnings base. The denominator is earnings available to common shareholders, not EBIT or earnings before tax. Preferred dividends must be deducted from net income.
- Ignoring the marginal tax effect. In the elasticity definition, \(dE_C/dEBIT=1-T\) under the constant-tax model. The tax factor cancels in the debt-only shortcut, but only after the calculation is set up correctly.
- Subtracting preferred dividends as if they were interest. They are paid after tax. In the equivalent pre-tax denominator, use \(D_P/(1-T)\).
- Reporting DFL without a stated EBIT. The measure varies with the operating level, so the EBIT and fixed-charge assumptions should accompany the result.
- Treating a point measure as an exact forecast. DFL is a local percentage sensitivity. For a large EBIT change, recalculate common earnings directly at the new EBIT.
Check Your Understanding
For each problem, assume annual amounts, fixed financing charges, and a constant tax rate with the tax treatment used in this tutorial. Give DFL at the stated EBIT.
- A company has EBIT of $450,000, interest of $90,000, no preferred shares, and a 20% tax rate. Calculate DFL. (Answer: 1.25)
- A firm has EBIT of $600,000, interest of $150,000, preferred dividends of $45,000, and a 25% tax rate. Calculate common earnings and DFL. (Answer: Common earnings are $292,500; DFL is approximately 1.5385)
- A business has EBIT of $320,000 and fixed interest of $80,000, with no preferred shares and a 25% tax rate. Calculate DFL using both the shortcut and the point-elasticity definition. (Answer: 1.3333 by either method)
- Two hypothetical firms each have EBIT of $500,000 and a 30% tax rate. Firm A has no fixed financing charges; Firm B has $100,000 of fixed interest and no preferred shares. Calculate each firm’s DFL and identify which is more sensitive at this EBIT. (Answer: Firm A, 1.00; Firm B, 1.25; Firm B is more sensitive)
- A company has EBIT of $250,000, fixed interest of $240,000, no preferred shares, and a 20% tax rate. Find common earnings and DFL, and state why the value is high. (Answer: Common earnings are $8,000; DFL is 25; it is high because EBIT exceeds interest by only $10,000)