Wall Street stock futures are lower this morning after the sharp sell-off in Apple after the bell on Tuesday. The company had published a highly conservative forecast for the fourth quarter, suggesting that the stellar growth of recent months will be hard to extend.

Today’s must-read story is by Fortune’s Nina Easton who talked with Sharon Squassoni, director of the Proliferation Prevention Program at the Center for Strategic and International Studies, on the pros and cons of the historic Iran nuclear deal. Read more about how this deal could reshape international relationships.

Here’s what else you need to know to start your day.

1. Tech stock are set for a battering

Tech stocks around the world were sent sharply lower by the fall-out from Apple’s statement, along with similar disappointments this week from Microsoft, Yahoo and IBM. Chipmakers such as Infineon and ARM Holdings were their country’s worst performers in the first half of the European day.

2. Qualcomm could be considering a breakup.

Chipmaker Qualcomm (QCOM) reports its third-quarter earnings after the market close tomorrow, and investors will be looking for any word on the company’s plans for a strategic review. Such a review, which comes amid activist investor pressure for change, could include a potential breakup or returning more cash to shareholders, reported the Wall Street Journal earlier this week. Qualcomm is also expected to announce wide-reaching layoffs as its revenue falls slightly below estimates due to the loss of a key customer and other delayed smartphone launches that use their mobile chips.

3. American Express looks for new revenues.

American Express (AXP) has had a rough year so far. It lost two of its exclusive tie-ups, one with Costco and another with JetBlue, since the beginning of the year, and its stock has dropped about 15% over that same time period. Investors will be looking for word on how the world’s biggest credit card issuer plans to build up its lost revenue with it reports second-quarter results today. AmEx’s CEO has hinted that layoffs could be on the horizon to help boost the bottom line.

4. A new frontier for Alzheimer’s treatments.

New data on two experimental Alzheimer’s drugs are set to be released today, which could more clearly show their potential to slow down the progression of the debilitating disease. The first is Eli Lilly and Co.’s (LLY) solanezumab, which is now in Phase III studies, and the second is Biogen’s (BIIB) earlier-stage aducanumab. Both medicines work by blocking the beta amyloid protein which is the impetus behind the toxic brain plaque buildup that is a trademark of Alzheimer’s disease. Such mechanisms have previously shown strong hints of effectiveness. If the results are good, expect shares of the two companies to skyrocket.

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5. The state of U.S. home sales.

Sales of previously owned homes hit a five-and-a-half year high in May, helped by the surge of younger buyers who had until now struggled to find their way into the market. Existing home sales are likely to continue their strong run with an increase of 1.2% year-over-year in June, hitting an annual rate of 5.4 million units. That’s even faster than May, which had a seasonally adjusted rate of 5.35 million. Look out for the June update from the National Association of Realtors at 10 a.m. ET.

Additional reporting courtesy of Reuters.