Full-text sample article FREE from Taylor & Francis. Proyecto Tequisquiapan (PT) provides protective microfinance services in a small region of rural Mexico, including, importantly, open access deposit facilities. The authors report on new research which examined PT's record in enabling people with different degrees of vulnerability to build assets and protect themselves from both sudden shocks and more predictable demands for lump sums of cash. PT was found to be relatively more useful for the most vulnerable households.