Alternative Bank Schweiz (ABS) is a Swiss financial institution headquartered in Olten, Canton of Solothurn. Since opening its doors in 1990, ABS has positioned itself as an alternative to conventional banking, placing a strong emphasis on transparency, social responsibility, and environmental sustainability. The institution was founded with the support of organizations focused on social justice and environmental protection and was created to serve as a counter-model to profit-driven banks.

With more than 44,000 customers and over 9,400 shareholders, ABS's total assets exceeded 2.6 billion Swiss francs as of 2023. It ranked as the 67th largest bank in Switzerland by asset size, representing about 0.09% of the Swiss banking market. The bank employs around 90 staff and maintains a governance model notable for its comparatively high proportion of women in management positions.

ABS provides a suite of typical banking services—accounts, mortgages, investment funds—but it distinguishes itself by openly publishing information about its loans, subject to borrower permission, to demonstrate exactly where customer funds are used. The majority of its financing is directed towards social and ecological initiatives, such as renewable energy, organic agriculture, and affordable housing projects. The bank explicitly aims for "profit sufficiency," seeking only enough financial return to remain viable without pursuing profit maximization.

ABS also participates in collaborations such as the Global Alliance for Banking on Values, furthering its commitment to alternative, values-based banking. Prominent examples of its recent project support include sustainable business loans and joint microfinance initiatives in cooperation with global partners, notably focusing on social and ecological enterprises.