Heavy equipment maker Caterpillar's (CAT) 32 percent gain helped power the index higher, as the company handily beat estimates and anticipated a recovery by the end of this year. Diversified manufacturer 3M Co. (MMM) added 17 percent in July, and IBM (IBM) rose 12 percent, both of which also helped the Dow Jones Industrial Average significantly because of its weighting methodology. The Dow is price-weighted, with companies that have higher share prices making up a larger portion of the index; contrasting that is a capitalization-weighted index like the S&P 500, where a company's market cap determines its representation.

After starting the month down more than four percent, the indices staged a steady reversal that brought prices consistently higher. Notably, the CBOE Volatility Index -- a measure of the fear in the marketplace -- remained essentially flat, opening and closing the month just below 26. The SPDR Gold Shares ETF (GLD), another investment meant to profit from uncertainty or fear, was up 1.1 percent on the month.

The market rallied without a huge boost from financials, which saw mixed results after reporting earnings. The Financial SPDR ETF (XLF) gained 8.7 percent on the month, putting it roughly in-line with the performance of the rest of the market. Homebuilder stocks did see disproportionately large gains, however, with the SPDR Homebuilders ETF (XHB) rising more than 21 percent on the month.

James Cullen edits and writes at CollegeAnalysts.com. He has no personal position in the stocks mentioned above.