(I always confuse the English terms of under-grad, grad & whatever, in Europe we have bachelor (first 3 years of university, master (specialisation, 2 years after) and then possibly a PhD (paid research), so I'm going to use these terms, also my direct experience is Europe (Belgium) based although I have quite some contact with Americans and foreigners from other countries (China & Congo for example) in similar positions and with and people who have worked in different countries).
Let me give you my own background as an example first:
I had a science background when I left high school, studied math in my bachelor, with a slight specialisation in economical and actuarial math, then statistics in my master. Meanwhile, I've done a lot of training in actuarial math and a little in economics, mostly by teaching a friend who did this.
I worked on a PhD for 1 years, then stopped because I had lost all interest in it and I'm now working as a teacher/teacher assistant/scientific collaborator at university, all classes in statistics. Future, most likely I'll start another, more interesting PhD in half a year or so if I get the chance.
So, summarized, I have a background mainly in statistics with a broad knowledge of math and econometrics.
For career paths, I have applied for several jobs between my 1st year as PhD and my current position as teaching assistant. Jobs for statisticians, economical mathematicians, applied mathematicians, actuarial scientists, ... are everywhere.
In the end, shortly after I had an agreement for my current position, I got offered another position and even two months later companies who saw my profile at the time or whom I applied for at the time still called me (back) and kept asking if I was interested even after I told them I had a new job already.
When I talked to people with a similar background as mine, I get these same conclusions. The demand in people with a background in both mathematics/statistics and economics is huge and the pool of talent is ridiculously small. Although it is a very competitive environment and companies often want people with unrealistic background experience, the job opportunities are countless in most civilised regions.
Companies in many sectors, banks, federal or state organisations and especially large multinationals have a constant need for people who know how to chew on numbers and how to deal with them both in very practical applied ways and in very abstract models that users may never see.
What I often noticed too, is that there is also a smaller group of companies, for example banks, who often don't care what degree exactly you have and who don't value experience. If you can prove them you are good in a variety of economics, math and science, they will make sure they'll get you a job and give you the training you need on the fly. These jobs pay much less initially, but the experience can be a bonus in later parts of your career.
So, if you're planning on going for a math/statistics degree and you already have a decent background in economics and you're somewhat good in it, I can guarantee you that you'll never have to struggle to get a job.