Several explanations, including stabilization of branched alkanes by electron correlation, destabilization of linear alkanes by steric repulsion, stabilization by neutral hyperconjugation, and/or electrostatic effects have been advanced as possibilities.
sˈɛvɹəl ɛksplɐnˈeɪʃənz, ɪŋklˈuːdɪŋ stˌeɪbɪlᵻzˈeɪʃən ʌv bɹˈæntʃt ˈælkeɪnz baɪ ᵻlˈɛktɹɑːn kˌɔɹɪlˈeɪʃən, diːstˌeɪbɪlᵻzˈeɪʃən ʌv lˈɪnɪɹ ˈælkeɪnz baɪ stˈɛɹɪk ɹᵻpˈʌlʃən, stˌeɪbɪlᵻzˈeɪʃən baɪ nˈuːtɹəl hˌaɪpɚkˌɑːndʒuːɡˈeɪʃən, ænd slˈæʃ ɔːɹ ɪlˌɛktɹoʊstˈæɾɪk ɪfˈɛkts hɐvbɪn ɐdvˈænst æz pˌɑːsəbˈɪlᵻɾiz.