Abstract We study the largest particle-number-preserving sector of the dilatation operator in maximally supersymmetric gauge theory. After exploring one-loop Bethe ansatz for the underlying spin chain with psl ( 2 | 2 ) symmetry for simple root systems related to several Kac–Dynkin diagrams, we use the analytic Bethe anzats to construct eigenvalues of transfer matrices with finite-dimensional atypical representations in the auxiliary space. We derive closed Baxter equations for eigenvalues of nested Baxter operators. We extend these considerations for a non-distinguished root system with FBBF grading to all orders of perturbation theory in 't Hooft coupling. We construct generating functions for all transfer matrices with auxiliary space determined by Young supertableaux ( 1 a ) and ( s ) and find determinant formulas for transfer matrices with auxiliary spaces corresponding to skew Young supertableaux. The latter yields fusion relations for transfer matrices with auxiliary space corresponding to representations labelled by square Young supertableaux. We derive asymptotic Baxter equations which determine spectra of anomalous dimensions of composite Wilson operators in noncompact psl ( 2 | 2 ) subsector of N = 4 super-Yang–Mills theory.