Chapter 9 — Capital Budgeting (MBA)
NPV • IRR • MIRR • PI • Payback • Discounted Payback — with syntax cards, mini calculators, worked examples, and homework preloads.
Intro
Capital budgeting evaluates long-term projects by turning future cash flows into today’s value or by finding required returns. For this course, focus on:
- NPV (gold standard for value creation)
- IRR & MIRR (rates of return; MIRR fixes IRR’s reinvestment assumption)
- PI (useful when capital is rationed)
- Payback / Discounted Payback (speed of recovery; screening tools)
Slides (PPT)
If the embed is blocked by your LMS or browser, use the open-in-new-tab link.
Featured Video — What is Capital Budgeting? (Importance, Methods & Limitations)
Short primer covering definitions, why it matters, common methods, and limitations.
Excel Syntax (Quick Cards)
NPV
=NPV(rate, value1, value2, ...)
- Values occur at period ends
- Add CF0 separately: NPV(...) + CF0
IRR
=IRR(values, [guess])
- Array must include CF0 and all cash flows
- Guess optional; helps convergence & chooses root when multiple exist
MIRR
=MIRR(values, finance_rate, reinvest_rate)
- Needs at least one negative and one positive CF
- Uses explicit reinvest & finance rates
Profitability Index (PI)
PI = 1 + NPV / |CF0|
Payback
Time to recover initial outlay (undiscounted). Discounted payback uses present values.
Mini Calculators
Inputs
Outputs
Manual formulas used
- NPV = Σ CF_t / (1+r)^t
- IRR: if multiple sign changes, there can be multiple positive roots; we pick the root nearest your Guess (Excel behavior)
- MIRR: grow positives at reinvest rate, discount negatives at finance rate, then annualize
- PI: 1 + NPV / |CF0|
- Payback = years until cumulative CF ≥ 0 + fraction of final year
- Discounted payback uses PVs
In-Class Example — Single Project
WACC = 11%; CFs: CF0 = -800; CF1=350; CF2=350; CF3=350.
- Expected (from your notes): NPV ≈ 55.30; IRR ≈ 14.93%; PI ≈ 1.069; Payback ≈ 2.286 yrs; Disc. Payback ≈ 2.72 yrs.
Multi-Project Choice — IRR vs NPV
WACC = 7.5%. Mutually exclusive projects S and L:
| Year | 0 | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| S | -1,100 | 550 | 600 | 100 | 100 |
| L | -2,700 | 650 | 725 | 800 | 1,400 |
NPV Profile — Project S vs L (Interactive)
Cash Flows (editable)
Project S
| Year | CF |
|---|
Project L
| Year | CF |
|---|
Controls
Tip: Edit any CF cell and the chart refreshes automatically.
Crossover Rate — What it is and how to get it
Definition (plain English): The crossover rate is the discount rate where two projects’ NPVs are exactly equal—i.e., the point where their NPV profiles cross. Below that rate one project has the higher NPV; above it, the other wins.
How to compute (L − S, then IRR)
- Align years for both projects (pad missing years with zeros).
- Compute incremental flows = L − S for each year (including CF0).
- Compute IRR of that incremental series. That IRR is the crossover rate.
Excel: =IRR(Incremental_Flows_Range)
Incremental CFs (L − S)
| Year | Incremental CF |
|---|
At the crossover rate, NPV(L) = NPV(S). Ranking flips on either side of this rate.
Excel vs Math
Setup: Put 11% in B1. Cash flows in B3:B6: −800, 350, 350, 350.
A) Easiest — Named Ranges
- Select B1 → type Rate in the Name Box → Enter
- Select B3 → name CF0
- Select B4:B6 → name CFs
- Select B3:B6 → name Flow
=NPV(Rate, CFs)+CF0 =IRR(Flow) =MIRR(Flow, Rate, Rate) =1 + NPV(Rate, CFs)/ABS(CF0)
B) Plain Cells (no $)
Tip: Don’t copy these around—just paste once where you want the answers.
=NPV(B1,B4:B6)+B3 =IRR(B3:B6) =MIRR(B3:B6,B1,B1) =1 + NPV(B1,B4:B6)/ABS(B3)
Math (same numbers)
Teacher mode (optional): show $-anchored version
=NPV($B$1,$B$4:$B$6)+$B$3 =IRR($B$3:$B$6) =MIRR($B$3:$B$6,$B$1,$B$1) =1 + (NPV($B$1,$B$4:$B$6)+$B$3)/ABS($B$3)
Non-Conventional Cash Flows (Multiple IRRs)
Example: CF0 = −90,000; CF1 = 132,000; CF2 = 100,000; CF3 = −150,000. Hurdle (required return) = 15%.
What’s going on (plain English)
- IRR solves: \( \mathrm{NPV}(r)=\sum_{t=0}^{n}\frac{CF_t}{(1+r)^t}=0 \).
- With sign pattern − + + −, the NPV polynomial can have multiple positive roots ⇒ multiple IRRs (Descartes’ Rule of Signs).
- On the NPV profile (NPV vs r), you’ll see the curve cross zero more than once.
Short math derivation
What to do in practice
😵 No real/positive IRR? Use MIRR and NPV.
MIRR (15%,15%): — • NPV@15%: —
Excel IRR “guess” (which root shows up?)
Use a big guess to land on the high root (e.g., 40% → ~42.56%). Use a small guess (e.g., 10%) to land on the low root (~10.11%).
=IRR(B3:B6)) → tends to return the low root.😵 If you see #NUM!, try a different guess, check for at least one sign change, or switch to MIRR and NPV.
NPV Profile — see the two zero-crossings
Method Summary
| Approach | Description | Pros | Cons | Suitable Cases | Industry Popularity |
|---|---|---|---|---|---|
| Net Present Value (NPV) | Calculates the present value of cash flows, subtracting initial investment | Accounts for time value of money, provides direct measure of profitability | Requires accurate cash flow estimation, sensitive to discount rate assumptions | Long-term projects, capital budgeting | Popular in most industries, especially capital-intensive sectors like manufacturing, energy, and real estate |
| Internal Rate of Return (IRR) | Finds the discount rate that makes NPV zero | Easy to understand, considers time value of money | Can be misleading with non-conventional cash flows or mutually exclusive projects, assumes reinvestment at IRR | Projects with conventional cash flows, early cash inflows | Used across industries, especially finance, healthcare, and tech |
| Modified Internal Rate of Return (MIRR) | Similar to IRR, but assumes reinvestment at a specified rate | Corrects IRR’s reinvestment assumption, suitable for comparing different projects | More complex calculation than IRR, still less informative than NPV for absolute profitability | Projects where reinvestment rate is known | Less common, used in finance and advanced corporate finance projects |
| Payback Period | Time required to recoup initial investment | Simple, emphasizes liquidity, useful for quick screening | Ignores time value of money, cash flows beyond payback period, and profitability | Short-term projects, high liquidity needs | Common in small businesses and start-ups, used in risk-averse sectors like retail |
| Discounted Payback Period | Time to recoup investment considering time value of money | Considers time value of money, provides a more accurate payback measure than traditional Payback Period | Ignores cash flows after payback, profitability, and project lifetime | High-liquidity projects with cash flow risks | Used in industries with uncertain cash flows like tech and energy |
| Profitability Index (PI) | Ratio of PV of future cash flows to initial investment | Useful for ranking projects, particularly with capital constraints | Similar drawbacks as NPV for cash flow estimation, not suitable for mutually exclusive projects | Capital rationing scenarios, comparing projects with limited capital | Used in finance, utilities, and large capital-intensive industries |
Quick Quiz
Click to check answers.
Homework (Due with Final)
Question 1
Project with an initial cash outlay of $20,000 with following free cash flows for 5 years. Year Cash flows 1 $8,000 2 4,000 3 3,000 4 5,000 5 10,000 1) How much is the payback period (approach one)? ---- 4 years 2) If the firm has a 10% required rate of return. How much is NPV (approach 2)? -- $2456.74 3) If the firm has a 10% required rate of return. How much is IRR (approach 3)? ---- 14.55% 4) If the firm has a 10% required rate of return. How much is PI (approach 4)? ---- 1.12
Question 2
Project with an initial cash outlay of $60,000 with following free cash flows for 5 years.
Year FCF
Initial outlay –60,000
1 25,000
2 24,000
3 13,000
4 12,000
5 11,000
The firm has a 15% required rate of return.
Calculate payback period, NPV, IRR and PI. Analyze your results.
(2.85, $764.27, 15.64%, 1.013, accept the project)
Question 3: Mutually Exclusive Projects
1) Consider the following cash flows for one-year Project A and B, with required rates of return of 10%. You have limited capital and can invest in one but one project. Which one? (A’s NPV = 72.73, B’s NPV=227.27, so choose B) § Initial Outlay: A = -$200; B = -$1,500 § Inflow: A = $300; B = $1,900 2) Example: Consider two projects, A and B, with initial outlay of $1,000, cost of capital of 10%, and following cash flows in years 1, 2, and 3: A: $100 $200 $2,000 B: $650 $650 $650 Which project should you choose if they are mutually exclusive? Independent? Crossover rate? (mutually exclusive: A’s NPV=758.83 > B’s NPV = 616.45, so choose A; Independent, choose all positive NPV, so choose both; Crossover rate = 21.01%. The calculator does not work. Use IRR in Excel)
Homework Help Videos (Chapter 9)
Q1 Walkthrough
Q2–Q3 Walkthrough
Excel Template Help
Resources
Blog — IRR vs MIRR (Why MIRR is often better)
No interactivity here—just a crisp comparison you can reference in class or homework.
The issue in plain English
- IRR assumes interim cash flows are reinvested at the IRR itself (often unrealistic), can produce multiple answers (non-conventional cash flows), or no real answer.
- MIRR fixes this by using explicit rates: a finance (borrowing) rate for negatives and a reinvestment rate for positives. It produces a single, comparable return.
Definitions (math)
IRR: the rate \( r \) that makes NPV zero.
\( \mathrm{NPV}(r)=\displaystyle\sum_{t=0}^{n}\frac{CF_t}{(1+r)^t}=0 \)
MIRR (with finance rate \( r_f \) and reinvest rate \( r_r \)):
\[ \mathrm{MIRR}=\left(\frac{\mathrm{FV}_{\text{positives at } r_r}}{-\,\mathrm{PV}_{\text{negatives at } r_f}}\right)^{\!1/n}-1 \]
- \(\mathrm{PV}_{\text{negatives}}=\displaystyle\sum_{t:CF_t<0}\frac{CF_t}{(1+r_f)^t}\)
- \(\mathrm{FV}_{\text{positives}}=\displaystyle\sum_{t:CF_t>0} CF_t\,(1+r_r)^{\,n-t}\)
Excel formulas (no $ anchoring)
Tip: For MIRR, a good default is to use your hurdle/WACC for both the finance and reinvest rates (e.g., 10%). Ensure your range has at least one negative and one positive CF.
Worked example (numbers & steps)
Cash flows: CF0 = −1000; CF1 = 400; CF2 = 400; CF3 = 400. Use finance = reinvest = 10%.
Solve \( \mathrm{NPV}(r)=0 \) for r.
Result: IRR ≈ 9.70%
\(\mathrm{PV}_{\text{neg}} = 1000\) (only CF0 at t=0)
\(\mathrm{FV}_{\text{pos}} = 400(1.1)^2 + 400(1.1)^1 + 400 = 400(1.21+1.10+1)=400\cdot3.31=1324\)
\(\mathrm{MIRR}=\left(\dfrac{1324}{1000}\right)^{1/3}-1 \approx \mathbf{9.81\%}\)
Why MIRR can be higher (or lower) than IRR
- If the IRR is below your chosen reinvestment rate, MIRR typically comes out a bit higher (you assumed better reinvestment than IRR’s assumption).
- If the IRR is above your reinvestment rate, MIRR will come out lower (more conservative and realistic).
When to use what
- NPV remains the gold standard for accept/reject and ranking (value creation at the hurdle/WACC).
- MIRR is the most sensible single “rate of return” to report: it uses realistic reinvestment and returns a unique number.
- IRR is fine for quick intuition with conventional cash flows—but watch for multiple IRRs or conflicts with NPV.
Note: Calculators here are for instruction; for official work, verify in Excel/approved tools.