This is the first part of a series.By Zack Buckley and Glen Bradford, TheStreet contributors After researching more than 5,000 companies, we've come up with 50 stocks that we believe to be the most undervalued. While we don't know where they will be in the next year, as we cannot predict the market, we believe in the next five years investors will be very rewarded by purchasing these stocks. The purpose of this series isn't to go into great depth on the greatest opportunities in the world, but to cover enough to prove that listening to us in the future is worth your time. We will guarantee we've done much more research than our cursory summaries show. We are so emphatic about the prospects for these companies that we're going to China this summer to visit these firms. We obviously don't like our 50th choice as much as our first, so we have created a tier system for the companies. While we think they are all great buys, the articles are tiered beginning with our favorite companies and ending with slightly less attractive but still very undervalued companies. Our first company is HearUSA ( EAR), a potential buyout candidate, and only an $80 million concern. Siemens ( SI) has 600 million euros to purchase a company and can't purchase any company that competes with HearUSA. You do the math. HearUSA also is expanding its business across the U.S. Another U.S. company is DJSP Enterprises ( DJSP), our last U.S. company in the top 50. It services foreclosures in Florida and is expanding across the country. As we all know, foreclosures are sky high in Florida and high across the rest of the U.S. The price-to-earnings ratio right now is about 5. China Sun Group High-Tech ( CSGH) is a battery manufacturer in China with three main products -- cobalt carbonate, cobaltosic oxide and lithium cobalt oxide -- used in the production of lithium-ion batteries. It has a P/E of 8.33. For fiscal 2008, the company saw revenue growth of 46% and net income growth of 27%. Biopharm Asia ( BFAR.OB) is trading at a P/E of 4 and expanding quickly with 22% revenue growth in 2008. The company has its own line of Chinese traditional medicines and also is a distributor of pharmaceuticals. The stock seems too cheap not to own.