(AP Photo/Thanassis Stavrakis)

We’ve looked at the big winners in the stock markets in recent weeks. Now here are the losers: the stocks in the Russell 3000 that have dropped the most in 2012 (through December 17):

10. Gastar Exploration Ltd. (GST) down 74.0 percent

Gastar has an odd story: After a positive earnings reports back in April, the oil and gas producer based in Houston lost 20 percent off its share price in a week. One theory was that Chesapeake Energy, which owned a big chunk of Gastar, had begun selling off its stock for reasons of its own, but whatever the cause, Gastar never recovered. By October, Chesapeake had sued Gastar, and Gastar had lost more than half its value in the space of six months.

9. Emerald Oil (EOX)  down 74.3 percent

Based in Denver, Emerald began the year as Voyager Oil & Gas. As Voyager, the stock was up more than 30 percent by late February, when it purchased a huge acreage in the Bakken Shale. As the value of that land became less and less apparent, the stock slowly faded away over the course of the year. Voyager acquired Emerald, a subsidiary of an Australian gas company, over the summer, then decided to keep the Emerald name. In October, the newly branded company announced a 1 for 7 reverse stock split, which is never a good sign.

8. Groupon (GRPN) down 74.4 percent

Groupon’s troubles started on March 30, when it was forced to announce that losses for the fourth quarter of 2011 hadn’t been $42.7 million, as initially reported, but actually $64.9 million. It seems the company hadn’t accounted for customer refunds. The company lost 17 percent of its value in a single day, and by the first of September was off 83 percent from its February peak.

7. Radio Shack (RSH) down  74.9 percent

On January 30, Radio Shack issued a disappointing earnings forecast, signaling that the company would come in at 11 to 13 cents per share for the fourth quarter of 2011, rather than the 37 cents Wall Street was expecting. The Fort Worth, Texas, based retailer lost 30 percent of its value that day. By late November, the share price, which had been in the low 20s as recently as 2010, was down under 2.

6. OCZ Technology Group (OCZ) down 75.9 percent

OCZ is a manufacturer of solid state drives for computers based in San Jose, California. After turning away a takeover offer from Seagate, the company had to delay shipments for its flagship product, the Vector SSD. Then on October 10, OCZ notified the SEC that it wouldn’t be able to file its earnings report on time, adding that it would have a significant loss in the second quarter. The market doesn’t take too kindly to these sorts of things, and the stock fell 42 percent in one day.

5. Amyris, Inc. (AMRS) down  75.9 percent

Amyris, based in Emeryville, California, has a pretty cool business, making synthetic biology-based fuels as an alternative to petroleum-sourced fuels. Unfortunately, it’s not a very lucrative business. Back in 2011, when the company announced it was going to produce 50 million liters of a fuel called farnesene, its stock was above 30. As of a couple months ago, though, it had only produced 2 million liters, and the stock spent most of the year below 3.

4. Gevo Chemicals (GEVO) down 76.4 percent

Gevo, based in Englewood, Colorado, is in roughly the same business as Amyris, making fuels out of biotech products. In June, the company announced plans to raise $100 million to retrofit its factories with a new offering of stock, and the share price fell 22 percent in a single day. In September, the company announced it was going to stop making isobutanol, a mostly corn-based fuel that had been its bread and butter, in favor of more conventional ethanol. That day, the stock dropped 35 percent.

3. Apco Oil & Gas International (APAGF) down 81.8 percent

Though based in Tulsa, Apco runs several oil & gas operations down in South America. The stock had shot up in recent years, roughly tripling in price between September 2010 and July 2011. Most investors seem to think that was the anomaly, not the recent downturn; at its peak, the stock was heavily overvalued.

2. Education Management Corporation (EDMC) down  82.0 percent

Based in Pittsburgh, Education Management is in the for-profit college business. It’s been an awful year for that industry, as the government has moved to limit the amount of financial aid such schools can receive; the rival Apollo Group, which runs the University of Phoenix, lost more than 60 percent of its value this year. Education Management compounded the troubles with a $1.2 billion loss in its fiscal fourth quarter.

1. KIT Digital (KITD) down  92.7 percent

KIT is a distributor of video platforms based in New York City, where it moved from Prague over the summer. It started the year on a strong upswing, gaining 45 percent through February 9 — then everything fell apart amid massive accusations of fraud and mismanagement. The stock had already lost half its value when the CEO announced in November that because of accounting regularities, the company would need to restate financial results going back to 2009. It now may be delisted from the Nasdaq market. If you had put $10,000 into KIT stock back on February 9, your stake would now be worth $500.

For more from Tom Nawrocki, see:

S&P 500’s biggest winners in 2012

Top 10 stocks in 2012

The dividend scenarios