Regarding the matter of shares in companies that do business on Shabbat, we do not consider the purchaser of shares to be a purchaser of the business for they have no opinion in the business. And the purchaser does not want to be an owner, and doesn’t want part of the business, but only purchases the profits and losses.
Further, this purchase isn’t in accordance with Jewish Halacha, but only works according to the law of the land. Even though the shareholder can vote, this is only an illusion, because practically the owners leave themselves a majority of shares, so we cannot say that the purchaser of shares is an owner.
But to purchase many shares so the company considers your opinion is forbidden.