Using an accounting conservatism theory that reflects accounting's role in practice, we investigate the relation between two extensively used measures of conservatism: asymmetric timeliness of earnings and the market-to-book ratio (MTB). We predict and observe that when asymmetric timeliness is measured cumulatively over long periods, its relation with end-of-period MTB is positive. When asymmetric timeliness is measured over short periods, its dependence on beginning-of-period composition of equity value (EV) is responsible for its negative association with MTB. Further, asymmetric timeliness appears to measure conservatism more efficiently when it is estimated cumulatively over multiple periods.