Quantum chemical calculations were carried out to study the mechanism of degenerate 1,2-, 1,3-, and 1,4-hydride shifts in acyclic tertiary carbocations 2,3-dimethyl-2-butyl, 2,4-dimethyl-2-pentyl, and 2,5-dimethyl-1-hexyl. Stable structures and transition structures were calculated at the B3LYP and MP2 levels using the 6-31G(d) and 6-311G(d,p) basis sets. The potential energy profile for these degenerate hydride shifts has global minima potential wells that correspond to the two interchanging open-chain carbocation structures and a high lying local minimum corresponding to the symmetrically hydrido-bridged intermediates. Unsymmetrically hydrido-bridged carbocations were located as transition structures, The calculated energy barriers (at the MP4/ 6-311 G(d,p)//MP2/6-311G(d,p) level) for 1,2-, 1,3-, and 1,4-hydride shift are 3.9, 4.2, and 7.5 kcal/mol, respectively. The trend of the calculated energy barriers agrees with the experimentally observed values. Electron correlation using MP2/6-311 G(d,p) is superior to B3LYP DFT hybrid methods for structures with hypercoordinated hydrogens involved in three-center two electron C-H-C bonds.