Wa Alaikum As'salam,
Welcome to the board. May Allah Almighty continue to lead you to Islam. Ameen.
As to your question, companies that directly sell sinful things should be avoided regardless of how rewarding they may be. As to the other regular companies, such as Technology ones, pharmaceuticals and others, Muslims are divided regarding their stock market. Some consider it a form of game of chance, usury and unlawful money. Others consider it pure trading and investing. If you do invest in the stock market, then I advise you to buy in a variety of companies and not just one company.
Dealing with banks can be costly to you. Even the "Islamic banks" are not different from the others. If you take a loan to buy a house, for example, you'll still end up paying it back 3 fold. Dealing with banks in general is not usury to me, because you're dealing with a company, not an individual. For example, if I lend you
$1,000, then I am forbidden to require you to pay me back more than $1,000.
And if I forgive your debt altogether, especially if you're financially challenged, then it would be best for me:
2:280 وان كان ذو عسرة فنظرة الى ميسرة وان تصدقوا خير لكم ان كنتم تعلمون
[002:280] If the debtor is in a difficulty, grant him time Till it is easy for him to repay. But if ye remit it by way of charity, that is best for you if ye only knew.And if or when you give charity,
do not scandalize people with it:
2:263 قول معروف ومغفرة خير من صدقة يتبعها اذى والله غني حليم
2:264 ياايها الذين امنوا لاتبطلوا صدقاتكم بالمن والاذى كالذي ينفق ماله رئاء الناس ولايؤمن بالله واليوم الاخر فمثله كمثل صفوان عليه تراب فاصابه وابل فتركه صلدا لايقدرون على شئ مما كسبوا والله لايهدي القوم الكافرين
2:265 ومثل الذين ينفقون اموالهم ابتغاء مرضاة الله وتثبيتا من انفسهم كمثل جنة بربوة اصابها وابل فاتت اكلها ضعفين فان لم يصبها وابل فطل والله بما تعملون بصير
[002:263] Kind words and the covering of faults are better than charity followed by injury. God is free of all wants, and He is Most-Forbearing.
[002:264] O ye who believe! cancel not your charity by reminders of your generosity or by injury,- like those who spend their substance to be seen of men, but believe neither in God nor in the Last Day. They are in parable like a hard, barren rock, on which is a little soil: on it falls heavy rain, which leaves it (Just) a bare stone. They will be able to do nothing with aught they have earned. And God guideth not those who reject faith.
[002:265] And the likeness of those who spend their substance, seeking to please God and to strengthen their souls, is as a garden, high and fertile: heavy rain falls on it but makes it yield a double increase of harvest, and if it receives not Heavy rain, light moisture sufficeth it. God seeth well whatever ye do.www.answering-christianity.com/quran_moral_code.htmHowever, if I have a company that makes money and pays for a variety of expenses (salaries, bills, losses, etc...), and you borrow from that company
$1,000, then Islamically I am allowed to require you to pay back more than $1,000. This is because you're dealing with a business, not an individual.
Islam prohibits us from being greedy animals. Unfortunately today, however, we're living under the capitalist system of satan. This is not to say communism and socialism are not satanic also (ex: your workers eventually become part-owners of your wealth). So in my opinion, take it as it comes. If you have to buy a house to grow a family, then do borrow money from the greedy banks. If you have to borrow money to open a business, then do so. Take it as it comes. It is not your fault. Just be wise and don't end up trapping yourself with too much debt:
"He has only forbidden you carrion, blood, and swine, and that which has been consecrated to any other than Allah. But who is driven by necessity, neither craving nor transgressing, it is no sin for him. For Allah is Forgiving, Compassionate. (The Glorious Quran, 2:173)"I hope this helps, insha'Allah.
Take care,
Osama Abdallah