Millennials expect companies to serve them products that are innovative, fast and simple -- and that kind of startup-driven pace is forcing big corporations to follow suit.

So says Deborah Hopkins, who holds a dual role at Citi. As the company's "chief innovation officer," she's tasked with helping the 202-year-old institution act like more like a startup. And as CEO of Citi Ventures, the bank's venture capital and innovation arm, she's responsible for building up an investment portfolio that includes payment startup Square.

NBC News talked with Hopkins -- the former CFO of Boeing and Lucent, and twice named to Fortune's top 10 most powerful American women in business -- about how she chooses where to invest and why big firms should watch out for "Pac-Man" startups nibbling at their feet. (This interview has been condensed.)

How do you think about investing for the new generation of customers? Is it different?

The world we're living in demands new ways of working. No matter who you are, your customers are saying: If you want me, you've got to understand me. That’s not historically been the case. So getting into the mind of the customers is really game-changing and challenging across the board, no matter what your industry.

The younger generation is not all that interested in buying stuff. For our generation it was like, let's go get married and buy a house! Now even owning a car isn’t really a thing. The whole idea of leasing and sharing seems really comfortable for millennials. Any service has to be cool, simple and transparent, and after all that I might trust you. It’s extraordinary.

How do you choose which companies to invest in? Are you drawn to certain sectors, or is it more about the team?

We’re intently focused on bringing the outside in to Citi. We look at thousands of companies a year, and we invest in eight to 12 a year that we think could have a positive impact on our business. These meetings help us foster deep domain knowledge so we can understand what's happening in security, commerce and payments, data and analytics -- all of these fields that touch everyone now.

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The trick, which I cant say we’ve cracked yet, is how do we routinely bring that knowledge we’re collecting to the business? How do we bring that to those people on our front lines? It's a Pac-Man effect -- the chomping around -- today these startups might be nibbling your toes, but they're getting bigger.

Do those "Pac-Men" force Citi to change its approach?

I think traditionally, especially in the financial services space, products had a long gestation. There'd be requirements written, turn around, talk to this team, rewrite, test, talk to this guy again, test again.

Startups totally throw that model out. We’ve learned so much from how entrepreneurs survive. Big businesses don’t starve a new idea. But entrepreneurs live scarcely. That scarcity mentality -- OK, I've got six months of cash, now how do I create a concept and a prototype and get consumers to validate it? -- brings this incredible energy.

You meet with thousands of startups. How do you narrow it down and choose the handful of companies that ultimately get Citi Ventures' money?

You start with, what customer pain point are they easing? Is it unique? Is it first to market, especially in fields like cybersecurity where you need to keep ahead?

The next part is understanding the business model. How do they plan to make money, and does that model hold up? Is the idea so much of a breakthrough that it’s going to be a hard sell to consumers? And then the management team is critical. How many wins, failures, who they've worked with before.

But, all of that can be super exciting ... and then you get to the valuation and say, hmm, I don’t think so. We’re quite conservative in that sense. We prefer to see a company that has some revenue going. There are a lot of boxes to check.

It's a rigorous process. We have a tiered committee voting. Every team at Citi –- regulatory, risk, etc. -– has a bite. It's an art and a science. It’s a lot of due diligence, more than people realize.

Are there ever intangibles? Someone checks all the boxes, but you don't move forward?

Sure. Sometimes you get a gut feeling that something isn't right. And I've learned if I don’t listen to it, I could get kicked in the stomach later. We’ve walked away from deals -- ones I wish we were in now. But the valuation might have been too high, and so you can't get too hung up on that.

Rarely, you'll get that person who just knocks you out even if they don't hit all the checkboxes. With all of these guys, you have to be humbled by the job they have running their own business. The best part of my day is a meeting with a new entrepreneur.

Are you looking at certain sectors or trends in 2015?

We’re seeing more social lifestyle platforms dabbling with a "buy" button, and generally more embedding of payments into the user experience -- that’s pretty darn interesting. A lot of our customers are asking about cryptocurrency, and we think the conversation bitcoin started will continue.

Citi Ventures' executive team is all women, which is rare in this field.

I didn’t do that on purpose. But it's a subject I'm personally very passionate about. Our biggest exit [fraud detection service Silver Tail, which EMC acquired in 2012] was co-founded by a woman [Laura Mather].

I'm one of those who believes women are wired differently, and I'm just a huge advocate of diversity of thinking. If everybody comes from the same background, you do not get the right answers when you’re asking the tough questions.