PurposeIntellectual capital (IC) is essential to the success of new technology-based firms. However, young firms only possess some of the resources and capabilities needed to develop, produce and market their innovative products and services. Hence, many form alliances to access complementary resources. This paper investigates the signaling effect of technology-based start-ups’ stock of IC on alliance formation.Design/methodology/approachThis study analyzes primary data concerning specific classes of IC and the alliances formed. Data were collected from founders of 233 technology-based new ventures in the USA. Hypotheses were tested via hierarchical linear regression.FindingsThis study demonstrates that firms' IC, in the form of founders with doctorates and patents, is positively related to the classes of alliances formed. These stocks of IC send signals about credibility to the market for alliance partners, enabling the firms to form alliances and gain access to complementary resources. The number of founders with doctorates was positively related to R&D alliances and alliance partners in a similar place in the value chain as the focal firm. In contrast, the number of patents was positively related to total alliances, production-oriented alliances and alliances considered upstream from the focal firm.Originality/valueThis paper collects retrospective data from founders of technology-based new ventures. The research contributes to the literature with its results that founder human capital and patent portfolios are essential for technology-based firms' innovation and growth. However, little research has investigated how firms' possession of IC facilitates alliance formation. This paper investigates this connection explicitly.