I assume you mean a new topic for thesis research in Master of Business Administration with particular focus in finance. There are a large number of topics within Finance. Look for what matches your interests and determine the methodology (case study based or more generic, data collection or modeling, etc.). Here are some topics that might be of interest:
- Cost of climate change: How much is climate change going to cost us, both in the short term as well as the long term? If the climate actually changes by a certain degree, how will it affect the economy and what would be its cost?
- Financing the activities to prevent climate change: It would take a great deal of investment to support activities that may prevent climate change. How will those activities be financed and by whom? Special focus can be given to underdeveloped countries, who may not be able to afford these steps.
- Are software start-ups over-hyped in terms of market valuation?: Given that software start-ups do not have much fixed capital, is the high market valuation really worth it or will it lead to a crash sometime soon? (Example: $19 billion valuation for Whatsapp and $40 billion for Uber, etc.)
- Investment opportunities in Renewable Energy: What should be the strategy for someone who wants to invest in renewable energy options, given that many of them are low-yield or still in the research phase?
- Financing for a new venture (Bank vs. market vs. VC): Where should a new venture go to get capital: banks, VC or market? What should be the financing strategy for a new venture?
- Islamic banking vs. banking in the developed world
- Investment in African countries
Hope this helps.