Isaak Lagerman

Case study

10 / 10KTH · 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

Commerce beyond the theme.

A bilingual, headless storefront designed as an independent commerce product—with Shopify serving as the current backend, not defining the customer experience.

Red dragon illustration used as temporary artwork for the RUMMA commerce case study

Have a similar problem?

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

Start a conversation