Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Apple (NASDAQ:AAPL) is up nearly 3% today on an analyst upgrade and the excitement surrounding its event tomorrow. However, Apple's jump is not enough to give S&P 500 (SNPINDEX:^GSPC) life today: As of 1:30 p.m. EDT, the S&P 500 is relatively unchanged, and the largest exchange-traded fund tracking the S&P 500, the SPDR S&P 500 (NYSEMKT:SPY), is unchanged as well.

Tomorrow Apple is holding a press event where it is expected to announce updates to its Mac Pro desktop computer and MacBook Pro laptop, potentially the latest versions of its iPad and iPad mini, and perhaps even an iWatch. The Mac Pro release has been hinted at for some time by Apple through cinema ads that end with "Fall 2013."

Apple is a secretive company known for not having any leaks, so the expectations for new versions of the iPad and the iPad mini are based on information that analysts have gleaned from the company's suppliers, as well as channel checks on which inventory is out of stock. Updated versions make some sense, given that it's been more than a year since Apple launched the iPad Mini which has since become the best-selling tablet. Tablet sales are booming this year with total device sales expected of 184 million units, up 50% from 2012.

Apple's stock is up today after an analyst from Societe Generale raised his rating on the stock from "hold" to "buy" with a price target of $575. Just a month ago, the same analyst downgraded the stock from buy to hold and set a price target of $500. With the stock up 7% the past month, this looks like a catch-up move, rather than anything truly prescient.

AAPL Total Return Price Chart

AAPL Total Return Price data by YCharts.

Dan Dzombak can be found on Twitter @DanDzombak or on his Facebook page, DanDzombak. He has no position in any stocks mentioned. The Motley Fool recommends Apple. The Motley Fool owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.