Existing research has used real options theory to study corporate venture capital (CVC) investment, yet little work has empirically examined such investment in a comparative setting. In this paper, we begin to address this gap by investigating firms' investment mode choice between CVC and acquisition, which are alternative modes for pursuing external business development and corporate growth. We propose that when exogenous uncertainty elevates the value of real options, firms are more likely to undertake CVC investments rather than acquisitions. Furthermore, we suggest that the value of real options under uncertainty is contingent upon several factors, which may also shape firms' choice between CVC and acquisition. The results indicate that market uncertainty is positively related to firms' choice of CVC versus acquisition. In addition, investment irreversibility strengthens the effect of uncertainty, whereas growth opportunities surrounding the investment weaken the effect. Our empirical findings and the comparative approach we adopt to studying CVC investments and acquisitions have important implications for theory and research.