What is the ruling on working as a security guard in a complex that includes companies dealing in shares, usurious loans, investment, and the stock market?

It is impermissible to cooperate in performing a forbidden act in any form of assistance, even if it is merely guarding or cleaning, for Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." Companies that practice forbidden things, such as usurious lending or dealing in stocks through unlawful means, must not be assisted with guarding or anything else. The fact that the practitioners are disbelievers does not affect this ruling. It is permissible to remain in such work out of dire necessity until one finds another job. If there is fear of temptation (fitna), then emigration from the country becomes obligatory.