AbstractThis paper confirms the relative superiority of related‐diversification in terms of the financial performance of New Zealand companies, companies which are much smaller and less diverse than those which normally feature in this literature. To facilitate comparisons with other studies, financial performance is measured in three ways: return on equity; return on assets; and sales growth. Other independent variables controlled for are company size; risk; leverage; technological opportunity; and industry concentration. The effective rates of protection afforded manufacturing industries (export subsidies and import tariffs) are also confirmed as having had some positive bearing on company performanc