I’ve chatted to adcoms. It’s not easy to be admitted to both of those schools. The math requirements in order to be considered for admission are equivalent to a bachelor degree and they expect to see a rigorous economics curriculum. I’m enrolled in an economics program which uses calculus 3, intro linear algebra/differential equations, a Master of Arts program. I’m preparing for a PhD economics for similar reasons, corporate job and the rigor of economics studies, I like the most.
I assume you mean investment banking after PhD. That’s not a good idea. Most people become economists. You should study finance if you want to work in finance or financial economics or minor in finance. Look up the financial risk management certificate. Although there’s emphasis on economics and math, you won’t pick up on enough finance in an Econ program.
However, people do go into finance. Usually risk management, did my undergraduate internships in risk management. They like to see lots of math and finance courses.