Does This Valuation Of Castle Biosciences, Inc. (NASDAQ:CSTL) Imply Investors Are Overpaying?

How far off is Castle Biosciences, Inc. (NASDAQ:CSTL) from its intrinsic value? Using the most recent financial data, we'll take a look at whether the stock is fairly priced by taking the forecast future cash flows of the company and discounting them back to today's value. The Discounted Cash Flow (DCF) model is the tool we will apply to do this. It may sound complicated, but actually it is quite simple!

We generally believe that a company's value is the present value of all of the cash it will generate in the future. However, a DCF is just one valuation metric among many, and it is not without flaws. For those who are keen learners of equity analysis, the Simply Wall St analysis model here may be something of interest to you.

Crunching the numbers

We use what is known as a 2-stage model, which simply means we have two different periods of growth rates for the company's cash flows. Generally the first stage is higher growth, and the second stage is a lower growth phase. 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.

A DCF is all about the idea that a dollar in the future is less valuable than a dollar today, and so the sum of these future cash flows is then discounted to today's value:

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$220m

We now need to calculate the Terminal Value, which accounts for all the future cash flows after this ten year period. 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 2.0%. We discount the terminal cash flows to today's value at a cost of equity of 5.8%.

Terminal Value (TV)= FCF₂₀₃₀ × (1 + g) ÷ (r – g) = US$60m× (1 + 2.0%) ÷ (5.8%– 2.0%) = US$1.6b

Present Value of Terminal Value (PVTV)= TV / (1 + r)¹⁰= US$1.6b÷ ( 1 + 5.8%)¹⁰= US$907m

The total value, or equity value, is then the sum of the present value of the future cash flows, which in this case is US$1.1b. To get the intrinsic value per share, we divide this by the total number of shares outstanding. Relative to the current share price of US$60.3, the company appears reasonably expensive at the time of writing. Remember though, that this is just an approximate valuation, and like any complex formula - garbage in, garbage out.

The assumptions

The calculation above is very dependent on two assumptions. The first is the discount rate and the other is the cash flows. You don't have to agree with these inputs, I recommend redoing the calculations yourself and playing with them. 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 Castle Biosciences 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 5.8%, which is based on a levered beta of 0.814. 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.

Moving On:

Although the valuation of a company is important, it ideally won't be the sole piece of analysis you scrutinize for a company. The DCF model is not a perfect stock valuation tool. Preferably you'd apply different cases and assumptions and see how they would impact the company's valuation. If a company grows at a different rate, or if its cost of equity or risk free rate changes sharply, the output can look very different. Why is the intrinsic value lower than the current share price? For Castle Biosciences, there are three important aspects you should further research:

1. Risks: As an example, we've found 2 warning signs for Castle Biosciences that you need to consider before investing here.
2. Future Earnings: How does CSTL'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 High Quality Alternatives: Do you like a good all-rounder? Explore our interactive list of high quality stocks to get an idea of what else is out there you may be missing!

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

This article by Simply Wall St is general in nature. 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.

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The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.