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tokens: al. ( 2018 ) carried out polarimetric observations of the NEO (3200) Phaethon at very large phase angles. The analysis of their data led Devogèle et al. ( 2018 ) to conclude that Phaethon is most likely a collisional fragment of the B-class asteroid (2) Pallas, in particular a fugitive from Pallas’ family, confirming previous results based exclusively on spectral reflectance data by De León et al. ( 2010 ). The observations by Devogèle et al. ( 2018 ) and Ito et al. ( 2018 ) are also shown in Fig. 1 . We note that at phase angles ∼100° (not shown in Fig. 1 ), the two polarimetric datasets are not consistent: around phase angle 105°, polarization values from Ito et al. ( 2018 ) reach about 50 per cent while at phase angle 101°, Devogèle et al. ( 2018 ) measure only 38 per cent. An explanation for this discrepancy, possibly due to surface heterogeneity of Phaethon, is beyond the scope of this paper. However, at phase angles , it clearly appears that Bennu exhibits values of linear polarization much higher than those of Phaethon. Our measurements, as well as the very recent observations of (152679) 1998 KU2 (Kuroda et al. 2018 ) are the highest ever found for a NEO observed at large phase angles. Another Solar system object that exhibits such high-polarization values is comet C/1995 O1 (Hale–Bopp), which was observed by Manset Bastien ( 2000 ) in a 9 nm wide gas-free filter centred around λ = 694 nm. Hale–Bopp measurements are also shown in Fig. 1 . The resemblance between the polarimetric data of Bennu and those of Hale–Bopp is striking, and although reinforces the conclusion about similarity between F-type objects and cometary dust proposed by Kolokolova Jockers ( 1997 ), it should be treated with caution, due to the big differences between the two physical environments: in one case we have an obviously active and very large comet, in the other one a much smaller asteroid with no detection of a gas or dust coma. Our data show that the phase-polarization curve of Bennu is steeper than the extrapolation of phase-polarization curves of main-belt B-class asteroids observed at phase angles , and resembles that of F-class asteroids. At phase angles , the polarimetric behaviour of Bennu is probably in between that typical of the F and B classes. Dynamical modelling has suggested that Bennu has most likely have evolved from the Inner part of the Main Belt (IMB; a 2.5 au; Walsh et al. 2013 , and references therein) possibly within either the ‘New’ Polana or Eulalia families (Bottke et al. 2015 ). If this is true, taking into account the finding by Cellino et al. ( 2001 ) that most of Polana family’s members belong to the F-class, our polarimetry might support the hypothesis that Bennu originated in that family, since Eulalia is a C-class asteroid. Based on what is currently known about the similarity in polarimetric behaviour of the asteroid F-class and of some cometary bodies, (101955) Bennu could be compatible with cometary characteristics and a