  A maximum-likelihood method, tested as an unbiased estimator from numerical
simulations, is used to estimate cosmic bulk flow from peculiar velocity
surveys. The likelihood function is applied to four observational catalogues
(ENEAR, SFI++, A1SN and SC) constructed from galaxy peculiar velocity surveys
and Type-Ia supernovae data at low redshift ($z \leq 0.03$). We find that the
Spiral Field {\it I}-band catalogue constrains the bulk flow to be $V=290 \pm
30 {\,{\rm km}\,{\rm s}^{-1}}$ towards $l=281^{\circ} \pm 7^{\circ}$,
$b=8^{\circ +6^{\circ}}_{-5^{\circ}}$ on effective scales of $ 58 {\,{h^{-1}
{\rm Mpc}}}$, which is the tightest constraints achievable at the present time.
By comparing the amplitudes of our estimated bulk flows with theoretical
prediction, we find excellent agreement between the two. In addition,
directions of estimated bulk flows are also consistent with measurements in
other studies.
