By Amir Chireh Mehr | March 20, 2026
Cost of Capital
What is the right discount rate? What expected return is appropriate? And how does an institution determine its hurdle rate, anyway?
One might mistake these questions for the finance equivalent of a poetic trope or cliche; however, these deceptively simple variations on the same question, namely, what is the appropriate cost-of-capital to use in capital allocation decisions, represent the single most misunderstood concept posed to me by students, colleagues, and fellow practitioners.
Most often, such conversations devolve into debilitatingly detailed debates destined for digressive discursion (and yes: that monstrosity of a sentence is meant to capture the inanity that often ensues). Should one utilize the capital-asset pricing model (“CAPM”)? Perhaps the dividend discount model is the most honest arbiter? Or maybe it is imperative to subscribe to the build-up method used in private transactions?
As the venerable Hafez of Shiraz famously quipped: some boast of wisdom, others spin tall tales; let us cast such judgements to the only Judge that matters.
Whilst numerous such analytic and academic frameworks abound, the conversation misses the point: one must first understand the problem at hand, and only then the appropriate tool. Said differently, it is self-evident that one ought to figure out which fastener is appropriate for a given surface — whether a screw, bolt, nut, or nail — before picking up a screwdriver, wrench, drill, or hammer.
As such, to continue with the analogy, the metaphoric surface of cost of capital has two layers: (i) opportunity cost; and (ii) risk profile and time horizon.
Opportunity cost is a delightfully simple but seldom understood concept within finance and economics. We make opportunity-cost-related decisions day in and out. Should I spend five dollars on coffee now, or save it for a bagel with cream cheese later? Should I watch the next episode of Slow Horses, or go for a bike ride this afternoon?
When it comes to cost of capital, opportunity cost is even simpler: what else could I be doing with this money? This is the first question everyone should consider when making a capital allocation decision. Whilst the trade-offs of going on a vacation now versus spending the money on home repairs are unmistakable, we often forget to ask the same question about capital, as jargon such as risk-free rates may obscure the simple fact that we are presented with a choice that should be measured against the next-best alternative.
Once that opportunity cost is understood, the second layer naturally emerges. If I am making an investment or lending decision that deviates from the next-best alternative, then what are the risks involved? Is the additional compensation provided by this alternative approach sufficient to justify the additional risks borne? And how might such risks change over time?
For those poor souls who have read thus far, you may have noticed that I am simply saying the following:
Cost of Capital = Opportunity Cost + Risk Premium
In truth, all the above frameworks are little more than different attempts at measuring these two quantities, dressed up in elaborate mathematical symbols and Greek characters.
Do not mistake that for me throwing my hands up and saying the tools are all the same or that they do not matter; rather, the bigger takeaway is that it is imperative that one both understand the true opportunity cost of an investment and the associated risk premia. Said another way, once you know you need a nail, grab a hammer.
Pivotal180’s project finance modeling courses are designed to familiarize anyone from analysts to the C-suite with the knowledge and skills to build, analyze and communicate clearly about project finance models:
Course participants will learn how risk is allocated between lenders and sponsors, understand the structure and drivers of project finance transactions, and gain the necessary skills to run and evaluate operational or financing scenarios required to identify the most substantial risks and opportunities for any deal.
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