Drift type and kinetic ballooning modes for negative magnetic shear are studied by taking effects of trapped electrons into account. Eigenvalues of the modes are calculated by using a gyrokinetic shooting code. The trapped-electron- mode is found to have almost the same characteristic features as those for positive shear in the electrostatic limit, except it is not stabilized by finite effects. Trapped electrons can cause appreciable reduction in the growth rate of the kinetic ballooning mode. Complete stabilization may occur in the short wavelength regime.