Being a socializer Gemini will always need to have good cash flow to empress the audience or people they transact with on daily basis. They are generally intelligent and are able to see money making opportunity earlier than others. They have great influential circle to guide them. Therefore, Gemini natives generally are able to make good money.
The risk-taking ability of Gemini can also help them earn from stock market or from speculative endeavors. However, they generally lack patience which is really the most important ingredient to become successful in investor or trader. If at all they work on improvement of their patience they can become highly successful with respect to finance