There seems to be a discrepancy between the ratio of dark matter to normal matter in the Universe (about 5 to 1 according to $\Lambda$-CDM) and the ratio of the average dark matter halo mass to the mass of the galaxy it contains (somewhere between 50 to 1 and 100 to 1).
As far as I am aware, most of the ordinary matter in the Universe is in galaxies, each of which have a dark matter halo on average at least 50 times as massive as the galaxy itself (see for example Guo, White, Li & Boylan-Kolchin 2010 "How do galaxies populate dark matter haloes?"). In addition, there are many smaller dark matter haloes which do not host galaxies.
Based on this, one would expect that the average ratio of dark matter to normal matter should be at least 50 to 1, yet it is only around 5 to 1. What is the reason for this?