Do you know about ShareGift?
It is common for shares in US Companies to be issued as a percentage of a share such as 6.738 shares.
In such cases, as the stock brokers and the market as a whole can only deal in complete shares, there is always the problem of the part of the share remaining (i.e. the 0.738 of a share as set out above).
In such a case you can transfer this part of a share to ShareGift who will then add it to other similar shareholdings and in due time the shares will be sold and the proceeds given to Charity.
ShareGift can organise such sale for no cost to the donor, and the donor can specify which charity is to benefit from the proceeds of sale in due time.
It is not uncommon for small shareholdings to be such that the costs of administration and of sale exceed the value of the shareholding, and again you can benefit a charity by using ShareGift.