NEW YORK -- Pessimism about Greece's financial problems returned to the financial markets Monday. Stocks fell sharply as investors once again doubted that the country will be able to avoid a debt default.

The drop ended five days of gains for stocks and marked the return of the back-and-forth trading that has accompanied the uncertainty about Europe's debt crisis.

On Monday, Greece's finance minister held an emergency teleconference with international creditors.

Investors also appeared pessimistic about a Federal Reserve decision expected Wednesday. Separately, President Obama called for $1.5 trillion in new taxes to help cut the deficit. For investors, the day's news added up to more uncertainty.

"The market just can't stand not knowing what's going on," said Ralph Fogel, head of investment strategy at Fogel Neale Partners in New York.

U.S. homebuilders felt more gloomy in September

WASHINGTON -- The outlook for U.S. homebuilders worsened in September, as foreclosures and anxious buyers hurt construction and sales activity.

The National Association of Home Builders said Monday that its index of builder sentiment in September fell to 14 from 15. The index has been below 20 for all but one month during the past two years.

Any reading below 50 indicates negative sentiment about the housing market. It hasn't reached 50 since April 2006.

Tyco International to split up into 3 separate businesses

NEW YORK -- Tyco International Ltd. said Monday it plans to separate into three independent, publicly traded companies. It will create an ADT North America residential security business and separate companies for flow-control products and commercial fire and security.

Tyco said the companies will have greater flexibility to pursue their growth strategies than under the existing structure.

Homebuilder Lennar sees quarterly earnings slide 31%

MIAMI -- Lennar Corp.'s fiscal third-quarter profit dropped 31 percent to $20.7 million as the company delivered fewer homes. Revenue dipped 1 percent to $820.2 million.

The builder, which has operations in Charleston, said Monday demand is picking up somewhat, driven by low prices and all-time low interest rates. Still, it conceded the uptick is being squeezed by tighter lending standards, high unemployment and weak consumer confidence.

Airbus, Boeing see Asia as hotbed for air service

PARIS -- Aircraft manufacturer Airbus said it expects the world's passenger fleet to more than double in the next 20 years to keep up with the demands of an increasingly wealthy population in the developing world.

The assessment, released Monday, forecast the world will need 27,800 new planes by 2030. That's an addition of $3.5 trillion worth of planes.

Much of the increase in traffic is expected to happen in Asia, particularly on domestic flights within India and China.

Separately, Boeing Co. warned Monday that Asia faces a shortfall of new pilots needed to meet surging demand and that it will get harder to recruit because the profession isn't desirable anymore.

Boeing predicted the region will need 182,300 new pilots from 2011 to 2030.