Mixed Companies: Zakat and Purification

Short answer: If the core business is haram (interest banking, alcohol, gambling), trading its shares is impermissible outright. If the core is halal but mixed with interest dealings, taqwa demands avoiding it; those who invest under shariah screening standards must purify the portion of income from haram sources by giving it away. Zakat on shares you own remains obligatory in all cases — haram admixture never waives zakat. Details: Purification money is given purely to be rid of it, without expecting reward, and can never be counted as zakat — 'Allah is pure and accepts only what is pure' (Sahih Muslim 1015). Zakat itself must be paid from halal wealth, per the share type (full market value for trading; the long-term method otherwise). Evidence: Quran 2:275 and 2:279 (riba); Sahih Muslim 1015; Quran 5:2 (no cooperation in sin); contemporary evidence-based scholars and fiqh boards on mixed companies and purification. For complex individual cases, consult a qualified scholar.