It has been months now since the Greek debt crisis first burst onto the stock market's radar screen. Even though several of the PIIGS countries had been experiencing stagnant growth and were plagued by loads of federal debt, the Greeks were the first domino to fall.

And fall they did. Check out how these Greek companies have fared over the past six months:

Company

6-Month Change (%)

Recent Price

Price-to-Earnings Ratio

National Bank of Greece (NYSE: NBG)

(58%)

$2.41

10.32

Hellenic Telecommunications (NYSE: OTE)

(48%)

$3.96

15.65

DryShips (Nasdaq: DRYS)

(44%)

$3.72

11.54

Navios Maritime (NYSE: NM)

(31%)

$4.76

5.97

Diana Shipping (NYSE: DSX)

(24%)

$12.09

8.51

Paragon Shipping (NYSE: PRGN)

(28%)

$3.58

2.98

Source: Yahoo! Finance.

Dry shipping hitting a floor?
Companies like DryShips, Navios, and Paragon Shipping ship dry bulk cargo such as iron ore, coal, fertilizers, and much, much more around the world. Revenues are primarily earned by charging fees to customers -- either through long-term contracts or based on spot rates. The Baltic Dry Index (BDI) is an exchange that measures the changes in the cost to transport raw materials, and is generally a good indicator of how the shipping business will perform. Yesterday, the BDI hit a 14-month low, marking 31 days of a consistent decline -- the largest drop on record. Typically, this would spell disaster for shipping companies.

Also, the threat of a double-dip recession in Europe and the U.S. makes some investors think twice about an economic recovery that would lead to increasing spot rates. However, surprisingly enough, DryShips seems to stand out in the crowd; its stock price has gone up 13% in the past week!

CAPS member goduwinravi seems to think that the stock still has nowhere to go but up.

This stock has fallen too much when compared to S&P and unless it goes out of business it is expected to see a big correction. Bad news about euro zone or greece will last only for so long and reversal is a clear possibility.

Could the other big-time Greek shippers follow suit?

Telecom companies, again?
A few days ago, I asked readers whether foreign telecom companies were finally getting cheap enough to buy. In particular, I liked Spain's Telefonica (NYSE: TEF) because it has been beaten down pretty badly because of the economy at home, although it gets about 65% of its sales elsewhere. It pays a solid 6.7% dividend, and with a recent European Union ruling, it has even more growth opportunities in Brazil. Hellenic Telecommunications doesn't have the type of diversification that Telefonica has, and as citizens in Greece get hit with more and more austerity measures, you have to assume this company's bottom line is going to take a hit. I don't think the stock is an absolute dud, but if you're going to take a risk on Greece, I think there are better places to put that hard-earned dough.

Banks, banks, and more banks
It's no surprise that the National Bank of Greece has taken such a beating over the past six months. As concerns about the government's ability to pay down debt spiraled out of control, despite the EU's extraordinary bailout package, investors have come up with many reasons to sell this stock. Earnings decreased in 2009, the outlook is grim for next year, and any future downgrades could destroy National Bank of Greece's ability to refinance.

However, the EU package of nearly $1 trillion provides plenty of backstop should things get worse. In addition, the bank isn't a one-trick pony: It has substantial growth opportunities in Turkey and plans to diversify even further. Trading at six times next year's earnings, there's a lot of upside for investors long National Bank of Greece.

The Foolish bottom line
Investing in Greece certainly isn't for the faint of heart. You have to be OK with the ups and downs of the market, extreme volatility, and the possibility that yes, everything could go down the tubes. However, there's enormous upside for many of these companies -- especially the bulk shippers, which don't even earn the majority of their revenues in Greece, but rather from the U.S. and the EU.

What do you think about the companies mentioned above? Do these beaten-down stocks deserve your investing dollars? Sound off in the comments box below.

Jordan DiPietro owns shares of National Bank of Greece and Telefonica. Try any of our Foolish newsletters today, free for 30 days. The Motley Fool has a disclosure policy.