We study how serial investors who regularly face unknown competitors attempt to make their projects dominant. Innovating in new markets often involves uncertainty over the nature of the final product and who the key competitors will be. Such projects also have long-term funding needs, so a commitment to provide the necessary funds imparts a strategic advantage vis-a-vis potential rivals. We show that cultivating a reputation as a reliable financier can create a desirable competitive advantage across an investor’s portfolio of projects. The downside is excessive reputation-seeking, which results in aggressive competition and over-investment in many product markets. Our results rationalize real-life aspects of innovation and provide new testable predictions.