07 / 08 · Business Analytics

Portfolio Optimisation

Decision modelling · LP / ILP / NLP

Built three Excel Solver optimisation models (linear, integer, and nonlinear) to construct an ASX equity portfolio under real sector, risk, and allocation constraints.

10 ASX stocks · 3 optimisation models

Excel SolverOptimisation

01 — The brief

Problem & outcome.

The problem

An investor holding ten ASX-listed stocks across five sectors needed a defensible way to allocate capital, maximising return under real constraints on sector minimums, single-stock exposure, and risk-category weighting, rather than picking stocks by feel.

The outcome

Built and solved three Excel Solver models: a Simplex LP for proportional allocation (1.37% monthly expected return under 13 constraints), a binary ILP for discrete stock selection (7 of 10 stocks), and a GRG Nonlinear model minimising portfolio variance via the full covariance matrix.

The binary ILP consistently excluded the same three weakest performers the LP had already zeroed out, cross-validating the recommendation across two approaches. The NLP flipped the objective, minimising variance while guaranteeing at least 1.50% monthly return. Sensitivity analysis showed the risk cap on the highest-risk assets was the most expensive constraint, worth roughly 0.027% of return per 1% it was relaxed.

02 — Key numbers

By the numbers.

10ASX stocks across 5 sectors
3optimisation techniques: LP, ILP, NLP
1.37%LP-optimal monthly expected return
13constraints in the LP model

03 — How it works

The model.

The Excel Solver LP model: objective function, decision variables, and all 13 constraints.

The Excel Solver LP model: objective function, decision variables, and all 13 constraints.

04 — Highlights

At a glance.

  • 10 ASX stocks, 5 sectors
  • LP: 1.37% monthly return
  • ILP: best 7-stock portfolio
  • NLP: minimum variance
  • 13 constraints
  • Sensitivity analysis