How to Allocate CAPEX: Optimally Allocating Capital Across Projects and Business Units

Optimally allocating CAPEX means determining, from all available investment opportunities, the combination of projects that generates the highest achievable overall financial or strategic value within the available capital.

The challenge begins as soon as there are more investment projects than available capital. At that point, it is no longer sufficient to evaluate individual business cases or rank projects based on ROI, NPV, or strategic scores.

Management must decide how to allocate limited capital simultaneously across projects, business units, locations, and multiple strategic objectives.

This is precisely where the real capital allocation problem arises.

The key question is not: Which projects are good?

But rather: Which combination of projects generates the highest achievable total value with our available CAPEX?

Table of Contents

• How to Allocate CAPEX Across Projects
• How to Allocate CAPEX Across Business Units
• How to Allocate Limited Capital
• How to Optimize Capital Allocation
• Why CAPEX Allocation Is a Portfolio Problem
• The Optimal CAPEX Allocation Process
• What Data Is Needed for CAPEX Allocation?
• Consider the Budget, Resources, and Dependencies
• Why Project Ranking Alone Is Not Enough
• Allocating CAPEX Across Business Units
• Example: Optimally Allocating 1 Billion Euros in CAPEX
• The Math Behind Optimal CAPEX Allocation
• What happens when CAPEX is reduced?
• Where does additional capital generate the highest value?
• Allocating CAPEX over multiple years
• CAPEX Allocation in Real Time in the Boardroom
• Optimize CAPEX Allocation with StratePlan
• Frequently Asked Questions About CAPEX Allocation

How to Allocate CAPEX Across Projects

Allocating CAPEX across projects means distributing available investment funds among competing projects.

For example, a company has 80 investment projects with a total capital requirement of 750 million euros. However, the available CAPEX is only 500 million euros.

This is not enough to finance all projects.

One possible approach is to evaluate each project individually and then create a ranking.

But a ranking only answers:

“Which project is more attractive when considered in isolation?”

For actual capital allocation, a different question is crucial:

“Which combination of these 80 projects generates the highest total value within a budget of 500 million euros?”

CAPEX allocation across projects is therefore a combinatorial portfolio problem.

How to Allocate CAPEX Across Business Units

The distribution of CAPEX across business units adds to the complexity.

For example, a corporation may have five business units:

• Business Unit A: 320 million euros in requested CAPEX
• Business Unit B: 270 million euros in requested CAPEX
• Business Unit C: 240 million euros in requested CAPEX
• Business Unit D: 210 million euros in proposed CAPEX
• Business Unit E: 160 million euros in requested CAPEX

In total, 1.2 billion euros in investment capital is being requested.

However, the company only has 800 million euros available.

A traditional solution might be to proportionally cut each business unit’s budget.

That’s simple, but it doesn’t answer the crucial question:

Does this allocation of the remaining 800 million euros generate the highest possible value for the company as a whole?

A portfolio-oriented CAPEX allocation therefore first moves away from existing division budgets and considers investment opportunities from the perspective of the company as a whole.

The optimization process can then take additional rules into account, such as minimum budgets for certain divisions, strategic priorities, or essential investments.

How to Allocate Limited Capital

Limited capital means that not all fundamentally attractive investments can be implemented.

This situation is often referred to as capital rationing.

Under capital rationing, management must decide which investments to fund and which to postpone, scale back, or cancel.

However, the correct approach is not necessarily to simply eliminate the supposedly weakest projects.

The key factor is the interplay between the projects.

For example, a single project with a high expected return might require 200 million euros in capital. Several smaller projects could collectively require the same 200 million euros, yet together generate a higher total value.

The correct capital allocation therefore results from this combination.

Limited Capital + Competing Projects + Constraints = Portfolio Optimization Problem

How to Optimize Capital Allocation

Optimizing capital allocation means not merely distributing the available capital, but systematically seeking a better—or optimal—combination of investments.

The basic mathematical approach is:

Maximize the portfolio value within the available capital and subject to all relevant constraints.

The portfolio value can be defined differently depending on the company.

Possible metrics include, for example:

• Return on Investment
• Net Present Value
• Expected revenue
• Cash flow
• Strategic value
• Contribution to Growth
• Risk Reduction
• Utility
• A weighted combination of several criteria

This transforms a budget decision into a mathematical decision-making model.

Why CAPEX allocation is a portfolio problem

Investment projects are often developed individually within companies.

Each department prepares its own business case. Every project has investment costs, expected outcomes, and a strategic rationale.

However, the final decision is not made at the project level.

It is made at the portfolio level.

This is because, once a shared budget exists, the selection of one project automatically affects the funding options for all other projects.

This creates an opportunity cost decision:

If we finance this project, what other investment opportunities will we no longer be able to finance as a result?

A robust CAPEX allocation process must therefore consider the entire portfolio simultaneously.

The Optimal CAPEX Allocation Process

A structured CAPEX allocation process can be established in eight steps:

1. Identify projects: Consolidate all relevant investment opportunities into a single decision-making framework.
2. Define investment needs: Determine the capital requirements for each project.
3. Define value: Determine expected revenue, NPV, ROI, utility, or strategic contribution.
4. Set the budget: Define the investment capital that is actually available.
5. Model constraints: Take into account resources, dependencies, mandatory projects, and other conditions.
6. Optimize the portfolio: Mathematically analyze permissible project combinations.
7. Compare scenarios: Analyze alternative budgets and strategic assumptions.
8. Decide: Select the portfolio that best supports management objectives.

This shifts the process from a project-oriented budget approval to a portfolio-oriented capital decision.

What data is needed for CAPEX allocation?

An initial capital allocation calculation does not have to start with a complex data model.

For a simple financial portfolio, just a few data fields may suffice:

• Project ID
• Investment requirements or expenditures
• Expected revenue, NPV, or another target metric

The model can then be expanded.

Additional information might include, for example:

• Strategic criteria
• Resource requirements
• Project dependencies
• Mandatory projects
• Project durations
• Risks
• Business Unit
• Location
• Planning Period

What matters is not the largest possible volume of data, but a data model that adequately reflects the actual investment decision.

Take budget, resources, and dependencies into account

In reality, an investment portfolio is rarely limited solely by the overall budget.

Additional constraints can significantly influence the combinations of projects that can actually be implemented.

Typical conditions include:

• Maximum CAPEX budget
• Budgets for individual business units
• Resource limits
• Engineering capacities
• Mandatory projects
• Regulatory investments
• Project dependencies
• Projects that must be implemented together
• Projects that are mutually exclusive
• Minimum investments in strategic areas
• Annual budget limits

Mathematical optimization therefore does not simply seek the theoretically most valuable portfolio.

It seeks the most valuable portfolio that is actually permissible under the defined conditions.

Why a project ranking is not sufficient

Project rankings are helpful for comparing individual investments with one another.

However, they do not automatically solve the capital allocation problem.

Suppose there are three projects to choose from:

The available budget is 80 million euros.

Viewed in isolation, Project A has the highest value.

If Project A is selected, the portfolio value is 90 million euros.

If, on the other hand, Project B and Project C are combined, 80 million euros are also invested, but a total value of 130 million euros is achieved.

Thus, the best individual project is not part of the most valuable portfolio combination.

This is precisely why project prioritization differs fundamentally from portfolio optimization.

Allocating CAPEX Across Business Units

When allocating CAPEX across multiple business units, internal competition for capital often arises.

Each business unit can make a reasonable case, from its own perspective, as to why its projects should be funded.

However, corporate management needs a broader perspective.

Optimized capital allocation can therefore bridge two levels:

Corporate Objectives + Business Unit Requirements

At the corporate level, for example, total value can be maximized while simultaneously taking into account rules for individual business units.

Such rules might be:

• Business Unit A receives at least 100 million euros.
• Business Unit B may receive a maximum of 250 million euros.
• At least one strategic project per business unit must be implemented.
• Regulatory projects are mandatory regardless of ranking.
• Certain growth areas are given higher strategic priority.

As a result, capital allocation does not have to mean ignoring all divisional requirements. Rather, it makes these requirements explicit and predictable.

Example: Optimally Allocating 1 Billion Euros in CAPEX

A company has 120 investment projects across several business units.

The total capital requirement is 1.6 billion euros.

The available CAPEX is 1 billion euros.

This means that projects totaling at least 600 million euros must be excluded from the original investment pool or postponed.

A flat-rate cut of 37.5 percent across all divisions would mathematically solve the budget problem.

However, it would not address whether the remaining portfolio generates the highest achievable enterprise value.

The alternative approach is to consider the 120 projects collectively.

For each project, factors such as investment, expected value, strategic criteria, and relevant constraints are documented.

The optimization model then determines which permissible combination within the 1 billion euros generates the highest portfolio value.

This does not simply cut the budget.

It is reallocated.

The Mathematics Behind Optimal CAPEX Allocation

The number of possible project combinations grows exponentially.

With 50 projects, there are theoretically:

2^50 ≈ 1.13 × 10^15 possible project combinations.

With 100 projects:

2^100 ≈ 1.27 × 10^30 possible project combinations.

With 200 projects:

2^200 ≈ 1.61 × 10^60 possible project combinations.

This order of magnitude illustrates why manual portfolio selection and the consideration of only a few scenarios cannot capture the entire decision space.

Mathematical optimization structures this decision space using objective functions and constraints.

Put simply, the task is:

Maximize portfolio value

subject to:

Total investment ≤ available CAPEX

and subject to all other defined conditions.

What happens when CAPEX is reduced?

One of the most important management questions arises when the originally planned investment budget must be reduced.

For example:

“What happens to our portfolio if we can only invest 850 million euros instead of 1 billion euros?”

A linear cut would reduce the budgets proportionally.

Portfolio optimization, on the other hand, asks which projects—under the new budget—continue to be part of the most valuable permissible combination.

This reveals:

• Which projects remain in the portfolio
• Which projects are dropped
• Which projects will be replaced
• How the expected portfolio value changes
• Which strategic goals are affected
• How high the opportunity costs of the budget reduction are

This makes it possible to quantitatively analyze a CAPEX cut.

Where does additional capital generate the highest value?

Capital allocation also works in the opposite direction.

Management can examine what additional value an increase in the investment budget would generate.

For example:

“What additional benefits do we gain if the CAPEX budget increases from 500 to 550 million euros?”

The optimization model can calculate new portfolios for different budget levels.

This reveals which additional projects could be financed and how much the total value changes.

This analysis is particularly relevant for capital allocation decisions because additional CAPEX does not generate the same additional value at every budget level.

Management can thus examine where additional capital investment is particularly valuable and at what point the additional portfolio effect begins to diminish.

Spreading CAPEX Over Several Years

Many investment decisions cannot be optimized within a single fiscal year.

Large projects tie up capital and resources over multiple periods.

An investment initiated today can therefore impact the available budget for future years.

Multi-Year Capital Allocation takes into account, among other things:

• Annual CAPEX budgets
• Project start and end dates
• Annual investment requirements
• Resource requirements per period
• Project dependencies spanning multiple years
• Strategic Objectives

As a result, the management question shifts from:

“How do we allocate our CAPEX this year?”

to:

“Which sequence of investments will generate the highest achievable value over our entire planning horizon?”

CAPEX Allocation in Real Time in the Boardroom

During an executive board meeting, the conditions for an investment decision can change within minutes.

Typical questions include:

“Reduce the budget by 100 million euros.”

“Make these three projects mandatory.”

“What happens if Business Unit A receives at least 150 million euros?”

“Which projects will be added if we invest an additional 50 million euros?”

“What happens if we place greater emphasis on growth?”

In a traditional process, such questions often lead to a new analysis after the meeting.

StratePlan’s CAPEX Live Boardroom Simulation is designed to translate changed assumptions directly into new portfolio scenarios.

This allows different capital allocations to be compared with one another within the decision-making process.

Question. Calculation. Comparison. Decision.

Optimize CAPEX Allocation with StratePlan

StratePlan treats capital allocation as a mathematical portfolio optimization problem.

Projects, investment needs, expected outcomes, strategic criteria, and constraints are integrated into a single decision-making model.

This enables companies to examine, among other things:

• How CAPEX can be optimally allocated across projects
• How to allocate CAPEX across multiple business units
• Which projects should be selected when capital is limited
• Which portfolio mix generates the highest achievable value
• How budget cuts affect the portfolio
• What value additional capital generates
• How strategic priorities change capital allocation
• How mandatory projects and dependencies are taken into account
• How investments can be spread over several years

The central perspective always remains the same:

It is not the individual project that is optimized. The entire portfolio is optimized.

Frequently Asked Questions About CAPEX Allocation

How to Allocate CAPEX Across Projects?

CAPEX should be allocated across projects by considering investment needs, expected value, and relevant constraints together. When there are many competing projects, mathematical portfolio optimization can be used to compare combinations of projects within the available budget.

How to Allocate CAPEX Across Business Units?

CAPEX can be allocated across business units by considering projects from different business units within a single portfolio. In doing so, corporate goals as well as minimum or maximum budgets, strategic objectives, and other rules specific to individual business units can be taken into account simultaneously.

How to Allocate Limited Capital?

When capital is limited, investments should not be prioritized solely on an individual basis. The key factor is which combination of investments, within the available capital, generates the highest achievable total value while simultaneously meeting all relevant constraints.

How to Optimize Capital Allocation?

Capital allocation can be optimized by modeling the investment portfolio as a mathematical optimization problem. An objective function defines the portfolio value to be maximized, while budget, resource, dependency, and other constraints determine the permissible decision space.

How do you optimally allocate CAPEX?

An optimal CAPEX allocation considers all relevant investment opportunities collectively and seeks a feasible combination of projects that generates the highest defined portfolio value within the available budget.

Why is an ROI ranking insufficient for CAPEX allocation?

An ROI ranking evaluates projects individually. However, it does not automatically consider which combination of projects makes the most efficient use of the available budget. Several lower-ranked projects can collectively generate a higher total value than a single, higher-ranked project.

How are mandatory projects taken into account in CAPEX allocation?

Mandatory projects can be defined as a fixed constraint in the portfolio model. As a result, these projects must be included in every permissible portfolio combination, while the remaining capital is allocated optimally to the other investment opportunities.

How are project dependencies taken into account?

Dependencies can be mathematically modeled as conditions. For example, it can be defined that Project B may only be implemented if Project A is selected at the same time, or that two projects cannot be implemented simultaneously.

How can CAPEX be distributed fairly among multiple business units?

The allocation can be made transparent through explicit rules. These include, for example, minimum budgets, maximum budgets, strategic weightings, or mandatory investments. As a result, “fair” is not interpreted subjectively but is defined as a transparent decision-making logic.

What happens to the portfolio if the CAPEX budget decreases?

In the event of a budget reduction, the portfolio can be reoptimized within the new capital limit. This makes it clear which projects remain in the portfolio, which are dropped, and how the expected total value changes.

Can additional CAPEX be evaluated mathematically?

Yes. By performing calculations with different budget levels, it is possible to determine which additional projects would be included in the portfolio if more capital were available and what additional portfolio value this capital would generate.

Can CAPEX be optimized over multiple years?

Yes. Multi-Year Capital Allocation takes into account investment needs, budgets, resources, and project dependencies across multiple planning periods. This allows for the optimization of capital allocation over a multi-year planning horizon.