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Interest Income

Guide to Understanding Interest Income

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Interest Income

Interest Income Definition

Companies retain cash and cash equivalents on their balance sheet to ensure they have sufficient liquidity to meet short-term financing and working capital needs.

Cash not reinvested into operations is frequently invested into interest-yielding accounts such as the following:

These sorts of short-term investments typically carry low yields, but it still enables the company to earn a return and offset losses from having “idle” cash.

For most companies – excluding financial institutions such as commercial banks – interest income is reported in the non-operating items section of the income statement.

The interest earned is not considered a non-financial company’s core part of operations, i.e. it is not integral to the company’s normal course of business.

Interest Income Formula

A company’s interest income is determined by its projected cash balances and an interest rate assumption.

With that said, the interest income line item can only be calculated once the balance sheet and cash flow statement are complete.

Hence, interest income is considered one of the “finishing touches” of a 3-statement model.

Like its counterpart, interest expense, interest income is modeled when building out the debt schedule of a financial model.

The standard method used to forecast either type of interest creates “circularity” within a model.

The Excel formula for calculating interest income takes the average between the beginning and ending cash and cash equivalents balance, and then multiplies it by the interest rate earned on the cash.

Interest Income Formula
  • Interest Income = Average Cash and Cash Equivalents Balance * Interest Rate Earned on Cash

Companies occasionally will not report interest income on their income statement and will instead consolidate interest expense with interest income into a single line item called “Interest Expense, net”.

In such cases, it is important to find the individual interest expense and interest income amounts broken out separately, so that they can be referenced separately in the forecast.

Interest Income Calculator – Excel Template

We’ll now move to a modeling exercise, which you can access by filling out the form below.

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Interest Income Example Calculation

Suppose a company’s beginning cash balance was $20 million in 2020.

We’ll assume the net change in cash – i.e. the total movement of cash in the specified period – is an increase of $2 million across both periods.

  • 2020A
      • Beginning Cash Balance = $20 million
      • Plus: Net Change in Cash = $2 million
      • Ending Cash Balance = $22 million
  • 2021A
      • Beginning Cash Balance = $22 million
      • Plus: Net Change in Cash = $2 million
      • Ending Cash Balance = $24 million

Moreover, the interest rate earned on cash for both periods will be set at 0.40%.

  • Interest Rate = 0.40%

The formula for calculating the interest income in Excel is as follows:

  • =IF(Circ=0,0,Interest Rate*AVERAGE(Beginning Cash Balance,Ending Cash Balance))

While not necessary for our simple exercise, setting up a circularity switch is crucial in a properly integrated 3-statement model.

If the cell named “Circ” is set to zero, the formula calculates the interest as zero.

Conversely, the formula could also be set so that if the circularity switch is turned on, only the beginning cash balance is used for the calculation.

In 2020, the interest income comes out as $84k, which increases to $92k in 2021 due to the higher cash balance.

  • 2020A
      • Interest Income = 0.40% * Average ($20 million, $22 million) = $84,000
  • 2021A
      • Interest Income = 0.40% * Average ($22 million, $24 million) = $92,000


Interest Income Example Calculation

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