Every screening post I’ve written — the 33% debt line, the 5% income line, Amazon, Ford, Boeing — sits on an assumption I never said out loud: that it is permissible to own a share of a company that has some debt and earns some interest, as long as it stays under a limit. That is not settled. Scholars disagree, and the disagreement is on the record. If you haven’t chosen a side, the ratios can’t help you yet. First, what nobody disputes. "Allah has permitted trading and forbidden interest." (Qur’an 2:275, as rendered on quran.com.) "If you do not, then beware of a war with Allah and His Messenger! But if you repent, you may retain your principal—neither inflicting nor suffering harm." (2:279, The Clear Quran, Dr. Mustafa Khattab.) Jabir reported that the Messenger of Allah ﷺ cursed the accepter of interest and its payer, and one who records it, and the two witnesses, and said: "They are all equal." (Sahih Muslim 1598, Book of Musaqah, text as given on amrayn.com.) So a bank that lives on interest is not the case in question. Everyone agrees that is out. The question is the ordinary company — it makes cars, sells goods — that also carries a loan or holds cash in an interest-bearing account. Is owning a piece of it allowed? View one: no. The International Islamic Fiqh Academy, Resolution 63 (1/7), 7th session, 9–14 May 1992: "Prohibition is the primary judgment regarding participation in joint-stock companies that may sometimes engage in prohibited transactions such as Ribā-based transactions, even though their main activities may be lawful under Shariah." IslamQA, on the same question: "The contemporary scholars differed concerning the ruling on them, but the most correct view is that it is haram to buy shares in them, invest in them or promote them." The reason it gives: "The shareholder is a partner in the company based on the number of shares he holds, so he is a partner to every transaction into which the company enters, such as riba or other haram transactions." The page lists the Standing Committee, the Fiqh Councils of the OIC and the Muslim World League, and Dr. Muhammad al-‘Usaymi as authorities. The passage doesn’t say which of them concluded what, so I won’t either.