It’s missing the US Mk 1. From the wiki:
In 1917, the Mk 1 grenade was created.
However, it became apparent that the Mk 1 grenade was quite difficult to use in the field. The grenades were often not ignited properly before being thrown, and enemies would return the grenade, this time properly lit.
I think it makes more sense to tax the shares at the time they are received (as income). Then they can be taxed again at the time of sale if they have increased in value.