Finance studies on the impact of market timing (or “windows of opportunity”) have almost exclusively focused on publicly traded firms and initial public offering firms. We provide first-time evidence on the impact of market timing on the capital structure of private firms that raise initial equity crowdfunding (ECF). We capture market timing by differentiating between ECF campaigns launched in hot markets, characterized by high ECF volumes, versus cold markets. Our sample includes firms financed via either Crowdcube or Seedrs, the two largest UK ECF platforms. Consistent with the idea of hot markets serving as windows of opportunity, we find that in hot markets, ECF firms set higher targets, collect more overfunding, and thus raise more equity capital than ECF firms in cold markets. Surprisingly, however, and inconsistent with a market timing theory of capital structure, we fail to find differences between the leverage ratios of hot- and cold-market firms from the year of the ECF campaign. This finding is explained by hot-market ECF firms contemporaneously rebalancing their capital structure by attracting more debt, especially financial debt. We discuss the theoretical and practical implications of these findings.