A study of the colour-ordered one-loop amplitudes in N=4 SYM reveals a surprising property: numerically, the amplitudes have an Approximately Universal form A^{1-loop}_n ~ A^{tree}_n \times U_n, where U_n is helicity independent. This form is exact if the amplitude is a MHV amplitude, but has an "error" which is typically less than 1% for the six, seven and eight gluon NMHV one-loop amplitudes.
@article{arxiv.0903.4631,
title = {Approximate Universality of N=4 Super-Yang--Mills One-Loop Amplitudes},
author = {David C. Dunbar and James H. Ettle and Warren B. Perkins},
journal= {arXiv preprint arXiv:0903.4631},
year = {2009}
}