Constraints on companion mass and semi-major axis for Kapteyn’s star. HCI adds significantinformation (up to 68% more companions that can be detected for the minimum age and up to 29% for the maximum age), concentrated at companion masses of 5–10 M_Jup and semi-major axes of 15–25 AU. The detectable companions also increase by up to 41% for the minimum age and 16% for the maximum age at semi-major axes larger than the NaCo field of view.