Key Insights

• Using the 2 Stage Free Cash Flow to Equity, Inspire Medical Systems fair value estimate is US$266

• Inspire Medical Systems is estimated to be 33% undervalued based on current share price of US$177

• The US$220 analyst price target for INSP is 17% less than our estimate of fair value

Does the September share price for Inspire Medical Systems, Inc. (NYSE:INSP) reflect what it's really worth? Today, we will estimate the stock's intrinsic value by estimating the company's future cash flows and discounting them to their present value. We will take advantage of the Discounted Cash Flow (DCF) model for this purpose. Don't get put off by the jargon, the math behind it is actually quite straightforward.

Remember though, that there are many ways to estimate a company's value, and a DCF is just one method. For those who are keen learners of equity analysis, the Simply Wall St analysis model here may be something of interest to you.

Check out our latest analysis for Inspire Medical Systems

Is Inspire Medical Systems Fairly Valued?

We are going to use a two-stage DCF model, which, as the name states, takes into account two stages of growth. The first stage is generally a higher growth period which levels off heading towards the terminal value, captured in the second 'steady growth' period. To begin with, we have to get estimates of the next ten years of cash flows. Where possible we use analyst estimates, but when these aren't available we extrapolate the previous free cash flow (FCF) from the last estimate or reported value. We assume companies with shrinking free cash flow will slow their rate of shrinkage, and that companies with growing free cash flow will see their growth rate slow, over this period. We do this to reflect that growth tends to slow more in the early years than it does in later years.

Generally we assume that a dollar today is more valuable than a dollar in the future, so we need to discount the sum of these future cash flows to arrive at a present value estimate:

10-year free cash flow (FCF) estimate

("Est" = FCF growth rate estimated by Simply Wall St)
Present Value of 10-year Cash Flow (PVCF) = US$1.9b

After calculating the present value of future cash flows in the initial 10-year period, we need to calculate the Terminal Value, which accounts for all future cash flows beyond the first stage. The Gordon Growth formula is used to calculate Terminal Value at a future annual growth rate equal to the 5-year average of the 10-year government bond yield of 2.5%. We discount the terminal cash flows to today's value at a cost of equity of 6.3%.

Terminal Value (TV)= FCF₂₀₃₄ × (1 + g) ÷ (r – g) = US$414m× (1 + 2.5%) ÷ (6.3%– 2.5%) = US$11b

Present Value of Terminal Value (PVTV)= TV / (1 + r)¹⁰= US$11b÷ ( 1 + 6.3%)¹⁰= US$6.0b

The total value is the sum of cash flows for the next ten years plus the discounted terminal value, which results in the Total Equity Value, which in this case is US$7.9b. The last step is to then divide the equity value by the number of shares outstanding. Relative to the current share price of US$177, the company appears quite good value at a 33% discount to where the stock price trades currently. Valuations are imprecise instruments though, rather like a telescope - move a few degrees and end up in a different galaxy. Do keep this in mind.

The Assumptions

The calculation above is very dependent on two assumptions. The first is the discount rate and the other is the cash flows. If you don't agree with these result, have a go at the calculation yourself and play with the assumptions. The DCF also does not consider the possible cyclicality of an industry, or a company's future capital requirements, so it does not give a full picture of a company's potential performance. Given that we are looking at Inspire Medical Systems as potential shareholders, the cost of equity is used as the discount rate, rather than the cost of capital (or weighted average cost of capital, WACC) which accounts for debt. In this calculation we've used 6.3%, which is based on a levered beta of 0.929. Beta is a measure of a stock's volatility, compared to the market as a whole. We get our beta from the industry average beta of globally comparable companies, with an imposed limit between 0.8 and 2.0, which is a reasonable range for a stable business.

SWOT Analysis for Inspire Medical Systems

Strength

• Currently debt free.

Weakness

• No major weaknesses identified for INSP.

Opportunity

• Annual earnings are forecast to grow faster than the American market.

• Good value based on P/S ratio and estimated fair value.

Threat

• Revenue is forecast to grow slower than 20% per year.

Next Steps:

Valuation is only one side of the coin in terms of building your investment thesis, and it ideally won't be the sole piece of analysis you scrutinize for a company. It's not possible to obtain a foolproof valuation with a DCF model. Preferably you'd apply different cases and assumptions and see how they would impact the company's valuation. For example, changes in the company's cost of equity or the risk free rate can significantly impact the valuation. Why is the intrinsic value higher than the current share price? For Inspire Medical Systems, we've put together three important elements you should explore:

1. Risks: Take risks, for example - Inspire Medical Systems has 1 warning sign we think you should be aware of.

2. Future Earnings: How does INSP's growth rate compare to its peers and the wider market? Dig deeper into the analyst consensus number for the upcoming years by interacting with our free analyst growth expectation chart.

3. Other Solid Businesses: Low debt, high returns on equity and good past performance are fundamental to a strong business. Why not explore our interactive list of stocks with solid business fundamentals to see if there are other companies you may not have considered!

PS. The Simply Wall St app conducts a discounted cash flow valuation for every stock on the NYSE every day. If you want to find the calculation for other stocks just search here.

Have feedback on this article? Concerned about the content? Get in touch with us directly. Alternatively, email editorial-team (at) simplywallst.com.

This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.