The Fisher hypothesis asserts that a 1% increase in inflation will lead to a 1% increase in nominal interest rates, so that real interest rates are stationary. Thus, 〖qr〗_t and 〖qb〗_t defined by 〖qr〗_t=r_t-p_t and 〖qb〗_t=b_t-p_t are stationary, even if r_t b_t and p_t contain unit roots.