There may be one thing missing for the stock market to rally — Apple.
The world's most valuable company is a key name in all the major benchmark indexes. Apple's shares constitute a 4.7 percent weighting in the Dow Jones industrial average and 11.1 percent in the Nasdaq 100, according to FactSet. The company also represents 3.8 percent of the SPDR S&P 500 ETF, the largest weighting in the security that tracks the S&P 500 index.
Using Kensho, a quantitative tool used by hedge funds, CNBC ran a study to find out how correlated Apple is with the stock market indexes over the past three months.
Apple's correlation with the S&P 500 is 0.78 and 0.76 with the Dow Jones industrial average. A correlation of 1 would mean the two move in perfect lockstep.
The markets' exposure to Apple shares isn't helping lately. The tech giant's stock declined 9 percent since its March 12 close versus the S&P 500's 5 percent drop through Monday as investors grew worried over future iPhone demand.
With the company's fiscal second-quarter results after the market close Tuesday, the next big move for the stock market may be determined by how well Apple does.