(At 5:10 p.m. EDT)

The Dow Jones Industrial Average notched a sixth-straight winning session, led by a jump in Caterpillar ( CAT) and a handful of other components set to report earnings Tuesday.

The blue chip average once again finished at the highs of the session, up 104.21 points to 8848.15, putting the index in positive territory for the year. Perhaps more impressive, Monday's close is the highest for the Dow since Jan. 6, when it finished at 9015.

As I mentioned before, the Dow's biggest contribution came from Caterpillar, as the company was upgraded to buy by Bank of America-Merrill Lynch, even though the company claimed second-quarter results from the construction-equipment maker should be weak. The stock ended with a gain of $2.66, or 7.8%.

With Caterpillar set to report earnings early Tuesday, it will be curious to see if this is another case of buy the rumor, sell the news. When it last reported quarterly results, Caterpillar slashed its guidance for 2009 to $1.25 a share. Currently, the Thomson Reuters average estimate sits at $1.03 a share, indicating Caterpillar may have more cutting to do.

With such a big jump Monday, the Dow's direction Tuesday may now depend on whether investors will be able to brush away any disappointing news from Caterpillar as easily as BofA-Merrill apparently can.

Luckily for bulls, even if Caterpillar's news is bad, there will be plenty of other Dow members for investors to focus on. Coca-Cola ( KO), DuPont ( DD), Merck ( MRK) and United Technologies ( UTX) all will report before Tuesday's opening bell.

(At 12:40 p.m. EDT)

The Dow Jones Industrial Average has pushed into positive territory for 2009, lately up 63 points to 8807, thanks mostly to a 6.5% surge in shares of Caterpillar ( CAT).

Caterpillar is one of several Dow components to report quarterly results Tuesday, one of the busiest days for Dow members. In addition to Caterpillar, releases are also expected before the start of trading from Coca-Cola ( KO), DuPont ( DD), Merck ( MRK) and United Technologies ( UTX).

Expectations are highest for Caterpillar, though. On Monday, Bank of America-Merrill Lynch upgraded the stock to buy and raised the stock price target to $45. The firm said the second quarter may be weak for the construction company, but forecasts are already so low that it may not matter.

Indeed, analysts aren't expecting much from Caterpillar, which hasn't offered guidance for the second quarter. On average, Wall Street is forecasting earnings of 22 cents a share, down sharply from earnings of $1.74 a share during the same quarter a year ago. Caterpillar is also expected to say revenue fell 35% from a year ago to $8.86 billion, according to a Thomson Reuters survey of analysts.

Among the other Dow companies reporting Tuesday, United Tech gained 1.8%, DuPont rose 1.3%, Coca-Cola tacked on 0.5%, and Merck added 0.3%. On the downside, Bank of America ( BAC) was the biggest decliner, dropping nearly 5% after analysts cut earnings estimates for BofA.

Tuesday is merely the start of it all, though. Later in the week, reports will come from Dow members 3M ( MMM), American Express ( AXP), AT&T ( T), Boeing ( BA), McDonald's ( MCD), Microsoft ( MSFT) and Pfizer ( PFE).