Finance is ok!

I think the subject of statistical machine learning with applications to finance is better than the pure finance, with respect to your background of undergraduate mathematics.

回复3楼:Statistical Economics?

计量经济学？

数学背景不错，对概率统计更感兴趣的话可以选择计量方向，特别是金融计量方面，资产定价方向也不错。