Markets could face rocky week

Futures trading suggests a weak open today for U.S. stocks. Asian stocks slumped in Monday trading, and European stocks opened lower.

But that's not all investors should be thinking about. The government will offer its first estimate of gross domestic product on Friday. And it could be a stinker.

Among the earnings due this week are reports from McDonald's (MCD) on Monday; Apple (AAPL) on Tuesday; Boeing (BA), Ford Motor (F) and Caterpillar (CAT) on Wednesday: Amazon.com (AMZN), Facebook (FB) and Exxon Mobil (XOM) on Thursday; and Chevron (CVX) on Friday.

Why Spain continues to roil markets
The reason for the Asian pullback and the European sell-off was worries about Spain. The region of Murcia, in southeastern Spain, may need a bailout. Murcia would be the third Spanish region to warn about cash problems. Catalonia and Valencia have already signaled they need help.

Spain's banks already need help. There is a growing worry that the Spanish government will need to be bailed out.

Spain's 10-year bond yield hit 7.52% this morning, something that has never happened in the euro era.

The other issue was Greece, which could run out of cash soon -- literally -- if the eurozone and the IMF see the Greeks aren't meeting their austerity agreements. "If Greece doesn’t fulfill those conditions, then there can be no more payments," German Vice Chancellor Philipp Roesler said in a Sunday television interview.

The Greek and Spanish worries pushed the euro lower against the dollar. The euro was trading at $1.20919, its lowest level since 2005.

Here are the key issues for the week:

The euro's slump. It may actually good for Europe because it will make European exports cheaper, but the falling euro means the dollar is rising. That hurts U.S. exports and depresses corporate profits of big U.S. companies. IBM said currency translation forced it to reduce its reported second-quarter revenue by $1 billion. You will see the currency issue today when McDonald's reports, but it will be an issue all week, especially with Boeing and Caterpillar on Wednesday and 3M (MMM) on Thursday.

Apple's growth. Apple reports after Tuesday's close. There's a growing worry that sales growth for its iPhone may be slowing as some users delay purchases until its new iPhone 5 comes out in the fall.

The housing recovery. It may not be a big recovery, but housing is recovering. Partly it's due to fewer foreclosures coming onto the market. That's forcing big institutional investors to engage in bidding wars to buy up blocks of foreclosed homes as quickly as possible. But there is more construction of apartments, and even single-family home sales are showing strength. You can see this in the non-seasonally adjusted data from the National Association of Realtors recent existing-home sales. Sherwin-Williams (SHW) last week said paint demand is growing, with the North American market much stronger than Europe or Latin America. Thursday's pending home sales report from the Realtors will be important.

Ford's European business. Ford warned recently that its European operations may show a second-quarter loss because of the slumping economy. The question on Wednesday will be how bad is the European business and how will that problem affect Ford's U.S. results.

Facebook's first quarterly report as a public company. The social-networking site reports its second-quarter results on Thursday. And what investors may focus in on is the revenue growth rate. First-quarter revenue was up 32.5% from a year earlier to $901 million, but year-over-year growth rates have been slipping. 

Big Oil's challenges in a slowing economy. Crude oil in New York is off 7.5% this year and was headed lower today. So was Brent crude. It's a function of crude oil's being priced in dollars. If the dollar is higher, crude will move lower. That may affect the guidance offered by Royal Dutch Shell (RDS.A) and Exxon on Thursday and Chevron on Friday.

The flight to safety. Many investors are pushing cash to Germany and U.S. government securities to be sure their money is safe. Some short-term yields of German securities are negative, meaning investors are paying for the safety.