Context. Exoplanet demographic studies rely on large and homogeneous catalogues, yet stellar multiplicity remains incompletely characterised in many planet samples. Misidentified stellar companions can bias both stellar and planetary parameters, leading to ambiguous and incomplete conclusions about planet formation and evolution. Aims. We aim to construct a robust and reliable reference catalogue of S-type exoplanets, orbiting one component of a binary, for future investigations of planet formation and evolution in multiple-star environments, and to reassess exoplanet demographics by comparing planets hosted by single-stars and binary systems in a statistically consistent framework. Methods. We updated the PlanetS catalogue of transiting exoplanets by systematically identifying gravitationally bound stellar com- panions using Gaia Data Release 3 (DR3). Adopting a deliberately conservative classification, we distinguished binary and single-star systems and constructed a matched control sample of single hosts to mitigate selection and observational biases. Using this curated dataset of 860 transiting exoplanets including 133 S-type planets, we performed a comparative demographic analysis of planetary properties as a function of host multiplicity, stellar mass, and binary separation. Results. We find a binary fraction of 19.4% relative to the control sample (15.5% relative to the full single-star sample), consistent with previous estimates but derived from a larger and more homogeneous dataset. Significant demographic differences emerge in the giant planet regime, less affected by observational biases. We find that giant planets in binaries are more massive than their single- star counterparts and orbit closer to their host stars, making their radius more inflated. In particular, we derive that ∼ 50% of giant planets orbiting M-dwarfs are in binary systems, predominantly with separations < 1000 AU, a 2.6σ excess compared to FGK-type hosts, suggesting that stellar multiplicity plays a key role in the formation or survival of giant planets around low-mass stars. In contrast, the small planet regime shows no statistically significant difference in binary fraction across stellar spectral types, although current statistics remain limited. We further explored correlations between planetary properties and host-star metallicity, finding trends consistent with core-accretion expectations largely driven by the giant planet population. —

Arxiv-link: https://arxiv.org/pdf/2605.31523