Customer loyalty is an essential part of business performance. Many companies hope to keep their customers for a long time, even if possible forever. This study investigates the role of customer trust in mediating the effect of customer satisfaction on customer loyalty in Islamic banks in the city of Yogyakarta. About 150 respondents were selected as the sample using the purposive sampling method. Structural Equation Modeling (SEM) was used to test the hypothesis of this study. The results of the study indicate that customer satisfaction has a direct effect on customer loyalty. Besides, customer satisfaction indirectly affects customer loyalty by mediating customer trust. Thus, it can be said that customer trust successfully mediates customer satisfaction on customer loyalty. This finding is consistent with the results of previous studies.

Regional state company of drinking water Tirtamarta Yogyakarta had made a break through by developing products in mineral water. Hence, now they were building mineral water manufacturing called "Ayo". The aim of the study was to conduct a feasibility research of the new manufacturer in terms of marketing and financial aspects. Endorsed by the demand of targeted market in mineral water and strong suggestion from city state of Yogyakarta to develop the business, it was significant feasible. The financial study showed that payback period was faster than the targeted investment period. Net present value (NPV) generated positively. Benefit cost ratio (BCR) was greater than 1 (one) and internal rate of return (IRR) placed in the range 14% was greater than the discount factor (DF) = 12%. Thus the business feasibility study in both marketing and financial factor concluded to be feasible to operate.