Let T, T′ be weak contractions (in the sense of Sz.-Nagy and Foia¸s), m, m′ the minimal functions of their C0 parts and let d be the greatest common inner divisor of m, m′. It is proved that the space I (T, T′) of all operators intertwining T, T′ is reflexive if and only if the model operator S(d) is reflexive. Here S(d) means the compression of the unilateral shift onto the space H2 ⊖ dH2. In particular, in finite-dimensional spaces the space I (T,T′) is reflexive if and only if all roots of the greatest common divisor of minimal polynomials of T, T ′ are simple. The chapter is concluded by an example showing that quasi-similarity does not preserve hyper-reflexivity of I(T,T′).