The excess orbital energy spectrum (EOES) analysis of exo-JP-10 chair/boat isomers provides further insight into the valence electronic structure changes in the isomerization process. The modest shifts in outer valence orbitals and the more significant changes in inner valence orbitals reveal specific bonding interactions in determining the relative stability of the isomers. The large excess energy in orbitals 22a and 25a, particularly, reflects the electronic response to the structural rearrangement of the isomers, with the exo-JP-10-chair configuration emerging as the more stable form due to its more favourable electronic interactions. This study adds to the understanding of how molecular geometry and electronic structure interplay in multicyclic hydrocarbons like JP-10, offering valuable insights for the design and optimization of highenergy-density fuels and to improve the fuel performance.