NEW YORK (Reuters) - The bears have been in firm control on Wall Street so far in September, and with anxiety about the health of the United States and world economies on the rise, they probably will not choose this week to go into hibernation.

Federal Reserve chairman Ben Bernanke said yesterday he strongly endorses the decision to place beleaguered mortgage finance companies Fannie Mae and Freddie Mac into conservatorship.

"These necessary steps will help to strengthen the US housing market and promote stability in our financial markets," Bernanke said in a statement.

The plan, however, was not expected to pull banking stocks out of the doldrums over the long term.

For the broader economy, recent data that showed the US economy continues to shed jobs and warnings from a raft of companies about diminished global demand slammed equity markets over the past week.

The three main US indexes lost more than 2.8 percent each, with the S&P 500 coming perilously close to a 2008 low set in mid-July. European and Asian markets also fell sharply.

With markets swooning, speculation that troubled hedge funds may be off-loading assets has only added to the unease, which analysts say will persist into this week.

"I'm not real optimistic right now," said Kurt Brunner, portfolio manager at the Swarthmore Group in Philadelphia. "Things are shaded more negatively now, and I don't see a whole lot of indicators that suggest positive momentum."

For one thing, markets have struggled even as the price of oil has continued a steady slide, down about 27 percent from its July record above $147 a barrel. While a positive for consumers, lower oil prices are also seen as a symptom of slowing global demand.

Companies, too, have forecast tougher times ahead, with Dell Inc predicting slower corporate technology spending and chip maker Qualcomm saying consumers have grown slower to upgrade their mobile phone handsets.

"There's been a strong contingent of economists who have been feeling that the economy was going to avoid a recession," said Sasha Kostadinov, portfolio manager at Shaker Investments in Cleveland.

"I think now those people who have been holding out are throwing their beliefs out the window. We've got a soft economy, credit is tight and the consumer is really struggling."

That leaves economic data front and centre in the coming week, with investors paying particular attention to reports on retail sales, first-time jobless claims and pending home sales.

Analysts said signs of further weakness, particularly after Friday's data showed unemployment hit a five-year high of 6.1 percent in August while 84,000 jobs were lost, would add to the stock market's woes.

"It will fuel expectations that the economy is in really bad shape and we'll see people talking about it falling into recession," said John Praveen, chief investment strategist at Prudential International Investments Advisers in Newark, New Jersey. "I don't think it will, but the recession talk will resurface, and that will have a negative impact."

While the US economy is undoubtedly fragile, Praveen said weak data could, along with a stronger US dollar and lower oil prices, put to rest one market fear: inflation.

That may set investors thinking that the Federal Reserve has room to cut interest rates again, which could boost consumer and business spending. To that end, he said, producer price data on Friday will be scrubbed for signs of softening price pressures.

There are other hurdles to clear, though, and some of them may prove high. Wall Street analysts have forecast additional write-downs in the third quarter for a number of financial firms, which Praveen said will keep pressure on the sector.

And only a week after dodging a bullet with Hurricane Gustav, Wall Street will be tracking the path of Hurricane Ike early this week as it gathers steam in the Caribbean.

Meanwhile, a firmer US dollar, which hit a year-to-date high against a basket of major currencies last week, may take the shine off export-driven companies, undercutting the one area of the economy that has been a top performer.

Signs of slower growth in the euro zone and Japan make that an even bigger concern. European shares shed some 5.8 percent over the last week on growth worries, their worst weekly loss in five-and-a-half years.