Since the first internet-only bank appeared in the US more than 20 years ago, internet-only banks in Asia and in Western countries have gradually developed different business models. During the last decade, internet-only banks in Asia have been applying such a development model -- using Fintech to embed banking service into their parent companies’ ecosystem. This study attempts to analyze whether or not such an ecosystem strategy is applicable in Taiwan. This study categorizes the three internet-only banks in Taiwan into the E-commerce category, the messaging apps category, and the telecommunications category. For each category, two representative cases are identified and studied. The case studies show some applicable strategies implemented by counterparties in neighboring countries, and the three internet-only banks in Taiwan will have to determine optimal sets of strategies that fit into their own ecosystem. By studying cases in neighboring countries, several key success factors for online banking businesses can also be defined: (1) the ability to raise capital, (2) technological competency, and (3) resource integration capability.