Isaak Lagerman

Case study

09 / 09KTH · B.SC. THESIS2023

An interpretable equity-valuation study comparing OLS with regularized regression models.

An equity-valuation study comparing interpretable regression with regularized models across the Stockholm Stock Exchange.

KTH BSc thesis on equity-valuation regression

Challenge

The study examined whether financial fundamentals could statistically explain company market capitalisation while remaining interpretable enough to support meaningful conclusions and avoid the opacity of a purely predictive model.

My contribution

With a co-author, I built and tested OLS, Ridge, LASSO and Elastic Net models using Bloomberg data from 181 OMXSGI companies between 2010 and 2019.

Approach

Prepared and log-transformed the dataset, winsorizing observations at the first and ninety-ninth percentiles across variables including EBIT, assets, debt, ROIC, cash, EPS growth and earnings.

Tested heteroskedasticity and multicollinearity using Breusch-Pagan, robust standard errors and VIF diagnostics.

Compared regularized models with a reduced OLS specification, balancing predictive fit against interpretability.

Outcome

LASSO achieved the lowest prediction error, while the reduced OLS model was selected for interpretation and achieved a holdout MSE of 0.387; earnings was the strongest driver, EPS growth was counterintuitively negative and debt dropped out as insignificant.

Deliverables

  • Cleaned Bloomberg dataset
  • OLS regression model
  • Regularized model comparison
  • Academic thesis

Forecasting without friction.

A regulator-ready electricity-demand model adopted by roughly 25% of Swedish grid operators in its first year.

Rejlers electricity-demand forecast model engagement

Have a similar problem?

Bring the context, constraints and desired outcome. I can help define the most useful first step.

Start a conversation