By The Associated PressCliffs Natural Resources Inc. shares sank Wednesday after a Morgan Stanley analyst, pessimistic on the U.S. iron ore market, downgraded his rating on the company's stock. THE SPARK: Analyst Evan Kurtz cut the iron ore miner and coal producer to "Underweight" from "Equal-Weight" and slashed his price target by 61 percent, to $14. That suggests a 35 percent drop from Cliff's Tuesday closing price of $21.43. THE BIG PICTURE: Cliffs' share price had already dropped nearly 70 percent over the past year. It posted a loss of $899 million for its last fiscal year, cut its dividend and issued a weak outlook for 2013. THE ANALYSIS: Morgan Stanley analyst Kurtz said that iron ore prices are falling again after a brief move higher earlier this year. That will hurt Cliffs. Beyond 2013, he sees problems in the U.S. with more supplies of iron ore coming into the market, which he believes will hurt Cliffs' sales volumes and prices. He also thinks shares don't yet reflect Cliffs' Asia business, where its reserves are winding down â¿¿ he predicted that its Koolyanobbing iron ore mine in Australia could cease production by 2020. Meanwhile, Cliffs' Canadian business is still saddled with high costs. Cliffs spokeswoman Pat Persico said that the company believes the estimates Kurtz is using for the long-term price for iron ore are too low. SHARE ACTION: Shares sank $3.04, more than 14 percent, to $18.39 by Wednesday afternoon. They hit a four-year low of $17.95 earlier in the day.