Credit unions are non profit and funnel money back to the account holders as I understand it. Not banks.
"Non-Profit" doesn't somehow mean magically ethical and not at all profit focused. The non-profit CEO salaries alone should make this obvious. You can clear a million a year in charge of a "non-profit."
How a credit union works, is like this.
Every member has a savings account and is sometimes referred to as a "shareholder", but the credit union is incorporated as a not-for-profit corporation. They register with the IRS as a tax-exempt business under 501(c)(6) meaning that profit must be re-invested in the organization instead of being paid out to a particular person. A credit union is therefore run by a Board of Directors that provide the long-term vision and an executive team to manage the day-to-day activities (typically President, Treasurer, various VPs, and the like although the titles vary). The executives who work at it as a full-time job are generally paid for the time they put in. Yet they are not automatically guaranteed their jobs: they must generally be voted in. The compensation in the not-for-profit world can be generous, and almost as egregious as in the for-profit corporate world, however unlike corporate salaries the salaries of the executive team are disclosed to the "shareholders" each of which has a vote when it's time to retain or get rid of the executive.
The way credit unions benefit their customers is by eliminating some of the fees associated with banking. Checking accounts for individuals are likely to have no monthly fee or a low minimum balance. There's no "investment" banking because there's no incentive to make obscene amounts of money by securitizing stupid things. Accordingly, most of the credit union's assets (i.e. the deposits and account balances of the members) are lent out to other members in the form of mortgages or perhaps credit cards. There's variety in terms of the deposits-- CDs and money market accounts are common-- and overall it functions like a savings-and-loan operation. Interest on a savings account is sometimes referred to as a "dividend" for a "shareholder". However "shares" in a credit union don't behave like shares of, say, Boeing or Apple. You can't sell them on a stock market. You sell them by withdrawing your assets from your account and closing it. Also, when it's time to vote for a new Board member or some similar issue decided by the members at large, you don't necessarily get votes proportionate to your investment in the credit union. Depending on your investment choices you may get a dollar return on your invested principal. The value of your shares will not go up and down like it would if you bought something on the stock market.
Credit unions are tax exempt in terms of not having to pay corporate income tax on the revenue earned from their loans or account fees, but donations to them are not deductible for itemized taxation purposes. Although many credit unions engage in charitable activities like money management classes for kids and teens and donations to the community, they are not "charities" as such and exist only for the benefit of their members. Membership is frequently restricted based on who the applicant works for, where he or she lives, or whether he or she is related to someone else who's a member.
My credit union giggled through the housing bubble because it made no subprime loans and did not purchase securitized "bundles" of subprime debt. Unlike a conventional bank, it had the option of basically flipping off the federal government which would otherwise have applied economic pressure to issue subprime mortgages. Its member base was, shall we say, not subprime material.
Many charities do become glorified support systems for the upper management (my book explains why and how), but credit unions are actually less prone to it because of the accounting transparency.