WaterStone Bank traces its foundational origins back to 1921 when it was established as Wauwatosa Building and Loan Association in Wisconsin. Over the decades, the institution evolved through disciplined regional community banking, expanding its physical branch network across southeastern Wisconsin. In the 21st century, it restructured its corporate governance under a mutual holding company framework, eventually operating as the primary subsidiary of Waterstone Financial, Inc. (NASDAQ: WSBF), offering comprehensive retail banking and national mortgage services.