Recent work has shown that dioxycarbenes can readily undergo homolytic fragmentations to radicals in solution. Previous workers have found some theoretical evidence for a transition state in the homolysis of dihydroxycarbene to HOCO and H radicals using the CISD method, but they were not able to conclude whether such a barrier was real or an artifact of the approximation. In this work the homolysis of hydroxycarbene is examined at the CAS and MRCI levels of theory using the cc-pVDZ basis set. The atomic and molecular properties are examined using the theory of atoms in molecules. At the highest level of theory, a transition state is round for the fragmentation of trans- but not of cis-hydroxycarbene. This transition state is rationalized in terms of the electronic states involved in the avoided crossing and by examining the evolution of several atomic and molecular properties during the homolysis. it is concluded that its origin can be traced to a mismatch of the electronic structures of these states in the region of the avoided crossing, best expressed by the dipole moments.