Persistence Without Predictive Advantage: Sponsor Histories and Cornerstone Adoption in Hong Kong IPOs

Abstract

Do repeated IPO intermediaries exhibit stable contracting histories, and do those histories improve genuine out-of-time prediction? We study 930 Hong Kong Main Board operating-company IPOs from 2018 through August 2026, 1,524 IPO–sponsor relationships, and 113 canonical sponsor entities. Sponsor histories use only strictly earlier listing dates. At the primary five-prior-deal threshold, the team adoption score has a raw AUC of 0.621 (year-stratified 95% bootstrap interval [0.571, 0.668]; within-year permutation p = 0.0004), while sponsor rankings persist across chronological halves (Spearman ρ = 0.610, p < 0.001). The controlled linear-probability coefficient is 0.390. Its p-value is 0.016 with leadsponsor clustered inference but 0.068 under a 4,999-draw wild-cluster bootstrap. Among single-sponsor IPOs the coefficient is 0.298 (clustered p = 0.081; wild-bootstrap p = 0.147), and omitting CICC reduces the full-team coefficient to 0.263 (p = 0.114). Expanding-window forecasts provide no stable incremental advantage: adding sponsor history changes pooled AUC from 0.691 to 0.682 (difference −0.009; bootstrap interval [−0.035, 0.017]). The difference is +0.030 in 2020–2023 but −0.040 in 2024–2026; the formal history-by-post-2024 interaction is imprecise (p = 0.660). Histories also do not predict release intensity or multi-tranche structure. Sponsor histories are persistent descriptors, but their association is dependence-sensitive and their predictive content becomes redundant as cornerstone adoption diffuses. The evidence is consistent with matching, networks, or routines rather than an exogenous sponsor effect or a portable forecasting advantage.

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