The Illusion of Precision in Valuation

The Ritual of the Model

If you’ve ever worked on a company valuation, you know the ritual. Dozens of Excel tabs, hundreds of rows, and countless hours spent arguing about margins, capital expenditures, tax rates, or discount rates. Analysts agonize over WACC and beta, about whether 9.2% is more defensible than 9.1%. Forecasts are stretched out year by year, with heroic levels of detail, sometimes as far as a decade into the future.

The end product is a valuation range, neatly boxed in a presentation. It looks serious, scientific, almost clinical in its precision. A boardroom of executives will nod as the model is unveiled, reassured by the complexity behind it.

But here’s the truth: most of that carefully built model does not drive the result. Sixty to eighty percent of the value usually comes from a single line at the end: the terminal value.

The Formula Everyone Relies Upon

The discounted cash flow model really has only two parts, and although it looks complicated it is pretty straightforward: the present value of the forecast period, plus the present value of everything that comes after it.

The first half of the DCF is where analysts spend weeks: building five to ten years of projections, line by line. They calculate the company’s free cash flow in each forecasted year, bring those flows back to present value, and add them up. This painstaking exercise typically explains only 20 to 40 percent of the company’s value.

The second half, the terminal value, is a shortcut. You take the last forecasted year of free cash flow, assume it grows forever at a constant rate g, divide by (WACC − g), and discount it back. That single formula usually explains 60 to 80 percent of the value.

So after hundreds of rows of forecasting, the result still depends mostly on one assumption about eternity. It’s like sitting a three-hour exam, answering dozens of detailed questions, and then discovering that 80 percent of your grade depends on the bonus question at the very end.

The Banker’s Job

On the sell side, the mandate is clear: maximize the client’s value. That means presenting the company in the best possible light, aligning assumptions with the highest reasonable comps, and showing a DCF that supports the valuation target.

On the buy side, the mentality flips. A private equity fund looks at the same company and asks: if we pay 100 today, can it realistically become 200 in five years? They stress-test assumptions, build LBO models, and model downside cases. Equity analysts issue price targets based on a mix of comps, sentiment, and catalysts. But even here, the DCF is always present. It sits in the appendix as the “sanity check.” And even here, most of the weight still comes from the terminal value.

So both sides build models with endless layers of assumptions. And both sides know that, in the end, most of the math comes down to one formula about forever.

How We Got Here

The idea of present value dates back to the 1600s. In 1671, Dutch mathematician Johan de Witt used it to value life annuities. In 1907, Irving Fisher popularized it in economic theory. The modern DCF, however, is credited to John Burr Williams, who in 1938 published The Theory of Investment Value. Williams argued that the intrinsic value of a stock is the present value of all its future dividends.

But projecting dividends forever was impractical, so in the 1950s Myron Gordon introduced a shortcut: the Gordon Growth Model. Assume dividends grow at a constant rate forever, and you can collapse infinity into a single formula. This is the basis of the terminal value we still use today. So the DCF we present in boardrooms in 2025 is basically Williams plus Gordon: 1938 plus the 1950s. Nothing fundamental has changed.

The Paradox of Precision

And that’s the paradox. We have agreed on a process with dozens of tabs and hundreds of lines, where analysts argue over margins in year 7 and the right beta for discount rates, only to have 60 to 80 percent of the valuation come from a formula that assumes a constant growth rate forever.

A 0.5% change in that growth rate can swing billions in valuation. The illusion is that we’re doing precise science. The reality is that most of the value comes from belief, belief that growth will persist, that markets will stay open, that the future will cooperate with our formulas.

DCF has survived not because it is perfect, but because it is useful. It disciplines thinking, it forces a structure, and it provides a shared language between bankers, investors, and analysts. But it is not science, it is art made with numbers.

In M&A, in equity research, in private markets, what really drives valuations and investment decisions are comps, sentiment, and catalysts. The DCF is just the ritual that makes those decisions look rigorous. And that ritual rests mostly on a single assumption about forever.