Copper was the darling of commodity traders. The price rallied from about $6,400 per ton to a record $10,190 in the past year, The Financial Times reports. Momentum was strong and it looked like there was no end in sight. But now, prices have dropped off a bit and miners are worried that the rally has hit a brick wall. The main concern is that what drove drove prices skyward -- China's demand -- may be slowing, according to the FT.

One indication of the slowdown is the amount of stocks held in exchange warehouses. At the LME Asia + Shanghai exchange warehouses, copper stocks have increased from below 150,000 to over 325,000 tons. That buildup has worried miners. The companies affected are Freeport MeMoRan (FCX), BHP Billiton (BHP), Xstrada (XSRAF), Anglo American and Brazil's Codelco, according to the Financial Times.

Wynn Resorts (WYNN - option chain) shares are rising today on news that casino revenue in the Chinese province of Macau rose 48% to $2.5 billion in March, according to government statistics. WYNN owns one of the six casinos operating on the island. If you think that the stock won't fall by too much in the coming months, then now could be a good time to look at a bullish hedged trade on WYNN.

WYNN opened this morning at $130.00. So far today the stock has hit a low of $129.71 and a high of $135.59. As of 11:50, WYNN is trading at $135.29 up $8.13 (6.4%). The chart for WYNN looks bullish and S&P gives WYNN a positive 4 STARS (out of 5) buy ranking.

In a recent letter to the governor of Illinois, Doug Oberhelman, CEO of heavy machinery maker Caterpillar (CAT), outlined his concerns about new state taxes that could force the Illinois-based company to move operations to another state. Reportedly, Wisconsin, Indiana and New Jersey are all courting the company.

With 23,000 Caterpillar employees in Illinois, the stakes are high. Hopefully, Governor Pat Quinn and Oberhelman will be able to work something out.

Watch the tape. Ignore the chatter. Those two are old truisms. The U.S. treasury market held firm Monday, with the 10-year June futures contract closing at 120-06, up 16 ticks.

There was some chatter from naysayers that China or Japan, the biggest foreign holders of U.S. debt, might decide to sell. That piece of news can be discarded. Why would they sell and take huge losses?

Stocks markets, however, across the globe were down, prompting a scramble for safety. Which safety? Why, the U.S. treasury market.

• BHP Billiton (BHP), the world's number one miner, had earnings before interest and taxes of $14.82 billion. Of that amount, iron ore accounted for $5.8 billion, up 177%
• Number three miner, Rio Tinto (RTPPF), had earnings of $26.6 billion. Iron ore unit accounted for 60%, or $16.6 billion, up 133% for the year.

When it comes to the biggest threat to world economies, oil scarcity is second only to nuclear war. What started in Tunisia, then spread to Egypt has now spreading to Bahrain and Iran, where protesters are clashing with police. In Iran, lawmakers are threatening death to protesters.

The fear of chaos spreading across the Middle East has sent the oil market into overdrive. Brent crude traded at $104 per barrel Tuesday.

For investors, the emerging markets have been a great place to find profits. No doubt, there are certainly risks, such as seen recently with the market turmoil in Egypt, but a diversified portfolio should solve these problems. Of course, it also helps to have lots of exposure to markets like China and Brazil.

According to Societe Generale, emerging markets may pale in comparison to the growth in commodities. Interestingly enough, it is rising commodities prices that is putting inflationary pressure on these countries. In other words, it is getting tougher for companies to pass along higher raw materials costs. As a result, there has been a rash of interest rate increases.

Baidu (BIDU), China's search engine giant, has seen its American depositary shares (ADSs) rise very nicely over the last 12 months. Yesterday, the ADSs closed up almost 2% to $108.63, not too far from the 52-week high of $115.04; the price movement was achieved on high volume. The 52-week low is $40.67, so those who bought in near the latter price are pretty happy campers.

That 2% rise, while quite respectable, wasn't the big story; rather, it was what happened during the after-hours session. The ADSs went up 7.7% to $116.99. Considering that we're in another earnings season, I don't think it's a particular challenge for anyone to guess what propelled the company to such lofty heights.

We have another crisis, this time in rare earth metals. China produces 95% of these metals and has said it would reduce exports by 35% in 2011. These moves are causing the prices of these metals to skyrocket, as reported in the The Wall Street Journal (subscription required).

Chemical refiners of gasoline use rare earth metals. The increased cost of the metals is being passed on to consumer and amounts to about a penny a gallon.

Molycorp (MCP) closed up 6% after China announced last week the lowering of its rare earth export quotas for early 2011. January 60, 65 calls and January 55 puts were active with total option volume of approximately 54K contracts. January call option implied volatility is at 80, puts are at 103; above its five-month average of 67 according to Track Data. Elevated put volatility suggests shares are difficult to borrow.

Atheros (ATHR) rallied 19% after CNBC reported that Atheros is close to being bought by Qualcomm (QCOM) for approximately $45 per share. Options were active according to Track Data.

Options Update is by Stock Specialist Paul Foster of theflyonthewall.com.

There is a big brouhaha in the rare earth metals sector. China, which produces 97% of these metals, has reportedly limited exports for 2011. Rare earth metals are necessary for everything from high powered wind turbines to iPhones.

As companies are scrambling to fill the gap, many have soared on the news. Here are some worldwide leaders, as reported by CNBC.com:

• U.S. Molycorp (MCP), which went public over the summer, is up 200%, and now trading at $49.90. Both Sumitomo (SMTOY) and Hitachi (HIT) have recently made deals with Molycorp. Molycorp plans to break ground on a new $500 million facility and expects to be extracting ore in late 2011.

According to the Financial Times, the Chinese Ministry of Information and Industry Technology called for a crackdown "on illegal VoIP (voice over Internet protocol) telephone services" and is collecting evidence for legal cases against them.

China is a big player in most markets; however, when it comes to technology, powerful local companies hold sway. Last year Google (GOOG) fought a battle to keep its website in China. A couple of years ago, China set rules whereby all Internet content had to pass through censors before being approved.