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Graham Number

The Graham Number is a formula developed by the legendary investor and “Dean of Wall Street,” Benjamin Graham. It serves as a handy, back-of-the-envelope calculation to estimate the theoretical intrinsic value of a stock. Think of it as a quick sanity check for investors looking for conservatively priced companies. The formula provides an upper price limit that a defensive investor should consider paying for a given stock. If the stock price is trading below its Graham Number, it's considered a candidate for further investigation, as it may be undervalued. The core idea is to find fundamentally sound businesses at a reasonable price, a central tenet of value investing. The calculation cleverly combines a company's earnings power with its asset value, providing a single, easy-to-interpret figure.

The Formula Unpacked

At its heart, the Graham Number is a simple mathematical expression. The formula is: Graham Number = Square Root of (22.5 x Earnings Per Share (EPS) x Book Value Per Share (BVPS)) Let's break down what these components mean and why they were chosen.

The Magic Number: 22.5

The number 22.5 isn't arbitrary; it's the product of two of Graham's key investment criteria for defensive investors:

Graham reasoned that multiplying these two maximums (15 x 1.5 = 22.5) created a reliable ceiling for a stock's valuation. By incorporating this constant, the formula automatically balances the relationship between price, earnings, and asset value. For example, a company with a very low P/B ratio could justify a higher P/E ratio, and vice-versa, as long as the combined product didn't exceed 22.5.

The Two Pillars: EPS and BVPS

The formula rests on two critical data points from a company's financial statements:

How to Use the Graham Number

Using the formula is straightforward. Once you calculate the Graham Number, you compare it to the stock's current market price.

  1. If the Market Price is below the Graham Number, the stock is potentially undervalued and warrants a closer look. It suggests you can buy the company's earnings and assets at a discount.
  2. If the Market Price is above the Graham Number, the stock is likely overvalued according to this specific metric, and a defensive investor should probably steer clear.

A Simple Example

Let's say you're looking at “Sturdy Manufacturing Inc.”:

First, calculate the Graham Number:

  1. Graham Number = √ (22.5 x $3.50 x $30.00)
  2. Graham Number = √ (2362.5)
  3. Graham Number = $48.61

In this case, the stock's current price of $75.00 is significantly higher than its Graham Number of $48.61. According to Graham's formula, this stock is overvalued, and you'd be paying too much for it.

A Word of Caution: Limitations in the Modern Market

While the Graham Number is a fantastic tool, it's not a magic bullet. It was developed in a different economic era, and investors must be aware of its limitations:

The Bottom Line

The Graham Number remains a timeless and valuable concept for today's investors. It’s a simple, conservative yardstick that instills discipline and helps you quickly identify potentially cheap stocks while enforcing a crucial margin of safety. While it shouldn't be the only tool in your analytical toolbox, it's an excellent starting point for any investor serious about fundamental analysis and finding true, durable value in the market.