The upward swing of the market over the past two months, with the Dow enjoying its longest run of positive performance in six years, was brought to an end last week. Heading into the month of May, there varying opinions among stock market investors as to whether the market is entering bear territory, or if this is a minor setback that will be resolved in the coming week.

Some factors that are likely to an impact on markets include the Gulf of Mexico oil spill which authorities and environmentalists are frantically attempting to contain. It is estimated that the oil spill will cost BP in excess of $3 billion, but the damage being done to the environment is incalculable. The disaster is also likely to put the hazards of offshore drilling under the spotlight. Another noteworthy event for investors is the proposed $3 billion merger of United Airlines with Continental Airlines, which was approved by the board of directors of both companies on Sunday.

In the financial sector, Goldman Sachs is the subject of much speculation, which has had a negative impact on the company, with share prices dropping around 22 percent in the last fortnight. Investors are no doubt keen to see what affect legendary Wall Street guru Warren Buffet's vote of confidence in the beleaguered financial giant, and its CEO Lloyd Blankfein, will have on its share price and the market in general, as speculation continues that precedents may be set with this case, which could resulting other firms being put under the microscope.

Highlights of the week ahead include first quarter results from Merck, Pfizer, Kraft Foods and Time Warner. On Monday, auto sales figures will be released throughout the day. Tuesday sees Merck reporting before start of trade, and Pfizer later in the morning. It is anticipated that revenue for Merck will have more than doubled in comparison to last year, with Pfizer at a fifty percent increase for the same period. Job creation and economic growth will be expounded by President Barack Obama and Treasury Secretary Timothy Geithner on Tuesday as well.

Before start of trade on Wednesday, Time Warner will release results, with revenue likely to have declined nine percent. The Joint Economic Committee in Washington will be holding a hearing focusing on job creation, and the services sector index compiled by the Institute for Supply Management will be out mid-morning. Kraft Foods will release its results on Thursday, and US chain stores will make April sales known throughout Thursday morning. No market-moving data is expected on Friday.