<b>Abstract</b>— <p>Using a virtual approach to the ternary fission of a compound nucleus (<i>A,</i> <i>Z</i>) formed by the capture of a thermal neutron by a target nucleus (<i>A</i> – 1, <i>Z</i>) as a two-step process, and using experimental energy distributions, estimated neck radii, and taking into account the fact that at maximum kinetic energies of emitted light charged particles, the penetrability factor for Coulomb barrier is close to unity, the formation probabilities of emitted third light nuclei were investigated. The calculations, performed in earlier studies within this approach, showed good agreement with experimental data on ternary fission with the emission of prescission α-particles. In this study, estimates of the light particle formation probabilities for ²³³U, ²⁴¹Pu, and ²⁴⁹Cf target nuclei during fission by thermal neutrons were obtained.</p>