Research Summary Strategic openness—firms voluntary forfeiting of control over resources—seemingly challenges the premise of the resource‐based view (RBV), which posits that firms should control valuable, rare, and inimitable (VRI) resources. We reconcile this apparent paradox by formalizing whether and when firms—consisting of resource bundles and deriving competitive advantage from exploiting selected VRI resources—may maximize profitability by opening parts of their resource base. As such, our paper refines RBV‐related thinking while supporting the theory's core tenets. Notably, we illustrate how a common‐pool resource can become a source of competitive advantage and how firms may use openness to shape inter‐firm competition. Managerial Summary Conventional wisdom holds that firms must control scarce and valuable resources to obtain competitive advantage. That being said, over the past decade many firms – amongst them Computer Associates, IBM, and Nokia – embarked on open strategies and made parts of their valuable resources available for free. These decisions pose an obvious conundrum, which we solve in our paper. We use a mathematical model, grounded in principles of the resource‐based view, to show why and under what conditions open strategies will succeed. Firms significantly improve their performance when (1) opening resources reduces their cost base while (2) strongly increasing demand for their still‐proprietary resource(s). We also explain how openness can reshape markets by weakening competitors, particularly in highly rivalrous environments.