Is a Jew permitted to invest in shares of a company if the company performs work on shabbas and a non-orthodox Jew started the company and is a major shareholder yet owns less than 50% of the shares of the company but still has more than 50% of the voting rights to override/block any takeover of that company?
This is a good and difficult question that needs some introduction to those less familiar with the relevant laws. Skip to the line break below if you don't want the intro.
A preview of the answer is that there is no issue to invest in such a company as a minority investor is not in a controlling position - therefore the workers are not working for the investor. See below for rationale.
The background is that a Jew is permitted to own a non-controlling amount of shares in a Gentile-owned company which operates on Shabbat.
R Yosef Kushner, the author of Commerce and Shabbos writes p. 324
This is because the Jewish minority shareholder is not in a position to decide the operating schedule of the business and the controlling partners are running the business on Shabbos by their own choice.
For a Jew to be the controlling partner or sole owner of a company that remains in operation on Shabbos, a number of requirements need to be met
- the day to day managing and running of the company is delegated to a non-Jewish CEO ("baal melacha")
- the Jew doesn't require the non-Jewish CEO to keep the business operating on Shabbos, rather he allows him to run the business as he sees fit
- the non-Jewish CEO receives a small percentage of the company profits in addition to his salary
- it is common knowledge that the Jew is not involved in the daily running of the business and is simply a financial backer in the company
For example the Orthodox financier Moshe Reichman once purchased an oil company which had to operate on Shabbat and asked R Shlomo Miller what to do, who in turned asked R Moshe Feinstein. Since the CEO/baal melacha was non-Jewish, RMF said there was no issue (heard from R Kushner at 24'40'' on this podcast).
Now I assume your question is on a company like facebook where the founder owns a minority of the shares but a controlling amount of them (60% as of April 16, 2018 according to Investopedia) and where both CEO and Deputy CEO are identifying as Jews.
Such a company does not meet the criteria above. Leaving aside whether the controlling stakeholder can work there halachically, another Jew might be prevented from buying shares in that company as he would become a partner of the Jewish controlling owner and be responsible for e.g., hilul Shabbat if the company has to operate 7/7.
I didn't find explicit differences in halacha between controlling shareholder and majority shareholder. A controlling shareholder can sell the company, change its strategy, direct its activities just as much as a majority shareholder. Even more so when he is also the CEO.
Now outside of Israel, it can be presumed that a majority of people working on Shabbat in such a company are non-Jews (since the majority of people outside Israel are non-Jews). Also in such a large company, the CEO doesn't directly direct work. So if there are Jews working on Shabbat, it is statistically likely that the managers ordering them to do so are non-Jews.
As such it is possible that one could apply the rulings of R Moshe Feinstein (Igrot Moshe Even HaEzer I:7) and R Yitzchak Weiss (Minchat Yitzchak III:1) who both permitted holding even the majority of shares of a company which is open on Shabbat as long as only non-Jews work on Shabbat (as reported here).
Also, and likely to be the most convincing, R Doniel Neustadt writes that
Most contemporary poskim rule that buying stock shares is not considered to be aiding and abetting Shabbos desecrators as there is no shortage of investors who are ready and able to buy shares. Anyone who buys shares does so for his own investment purposes and not for the purpose of financing the company.
Finally I asked your question to R Yosef Kushner who wrote the above book. He responded (and agreed to be quoted)
[There is no issue] to invest in that company as the investor is still not in a controlling position, so the workers are not working for the investor, and in terms of לפני עור (lifnei iver), that the investor is helping facilitate a transgression, that would not be an issue since they could easily run the company without the investors money.
The above are obviously only considerations to bring up before asking the question to a qualified rav.