Purpose The purpose of this paper is to examine how pre-IPO cash flow and earnings volatility influence both post-IPO pricing and valuation. This paper provides an empirical extension of Pástor and Veronesi’s (2003, 2005) argument that uncertainty surrounding a private firm’s expected profitability can impact how the firm is valued in the IPO aftermarket. Design/methodology/approach This paper includes a sample of 695 IPOs between 1996 and 2011. Pre-IPO financial statement data are hand collected from the EDGAR database. Pre-IPO cash flow and earnings volatility is computed using the standard deviation of the firm’s three years of cash flows and earnings prior to the IPO. Tobin’s Q serves as a measure of post-IPO firm valuation. This paper includes two subsamples to account for the “hot” IPO market of the late 1990s. Findings Firms with higher pre-IPO cash flow volatility are associated with higher post-IPO aftermarket valuations. This result holds for both the “hot” IPO and the later sub-sample. Pre-IPO earnings volatility does not influence aftermarket valuations, suggesting that only the uncertainty surrounding cash flows serves as a salient measure to IPO investors. Finally, IPO underpricing is associated with pre-IPO cash flow volatility, suggesting another channel in which IPO pricing is influenced. Research limitations/implications The hand collection for this paper is laborious and is limited to yearly cash flow and earnings numbers. The paper documents that quarterly and yearly cash flow and earnings volatility measures are highly correlated for the select stocks that allow for such testing. Further, a broader sample that accounts for more international IPO issues might corroborate the findings in this paper. Practical implications This study shows that investors both initially price and value IPO firms base on their pre-IPO cash flow volatility. Originality/value This is the first paper to examine the direct link between pre-IPO cash flow and earnings volatility on IPO aftermarket valuation and IPO pricing.