  The inclusion of charging and spin-exchange interactions within the Universal
Hamiltonian description of quantum dots is challenging as it leads to a
non-Abelian action. Here we present an {\it exact} analytical solution of the
probem, in particular, in the vicinity of the Stoner instabilty point. We
calculate several observables, including the tunneling density of states (TDOS)
and the spin susceptibility. Near the instability point the TDOS exhibits a
non-monotonous behavior as function of the tunneling energy, even at
temperatures higher than the exchange energy. Our approach is generalizable to
a broad set of observables, including the a.c. susceptibility and the
absorption spectrum for anisotropic spin interaction. Our results could be
tested in nearly ferromagnetic materials.
