This is the final part of a three part series analyzing First Bancorp (NYSE:FBP). For part 1, click here. For part 2, click here.

Value investor Joel Greenblatt has written that he likes to invest in great companies, but he will trade a lesser company if it is sufficiently undervalued. The difference is subtle, but critical.

When he discovers a company that's trading for a discount, he will buy it. If that company happens to be well managed, well positioned, and a market leader, he'll hold on to that company for the long term. To Greenblatt, that's an investment. That's the strategy that has made Warren Buffett, well... Warren Buffett!

But for a company that isn't quite so elite, Greenblatt will still buy shares, but he'll do so knowing that, once the valuation reaches a certain point, he's going to sell his stake in the company.

In the video below, Motley Fool contributor Jay Jenkins takes this approach, and applies it to struggling Puerto Rican bank First Bancorp. The bank is down nearly 40% so far this year, largely driven by the bank's struggling loan portfolio in the face of high unemployment and a struggling economy on the Caribbean island. But the tides may be changing -- trends in asset quality and on the income statement have turned and are now improving.

Is First Bancorp undervalued, fairly valued, or overvalued? And if it's a buy, is this bank an investment or a trade by Joel Greenblatt's definition? 

To find out, click on "play" below.