Tim Cook took the reins as CEO of Apple (AAPL +1.69%) on Aug. 24, 2011, when he replaced Steve Jobs. Since that date, shares of the consumer technology powerhouse have climbed a jaw-dropping 2,240% (as of Aug. 27). The company's market capitalization exploded from $349 billion then to $4.6 trillion today.
On Sept. 1, John Ternus will become the next CEO of Apple. He's stepping into the role after having been senior vice president of hardware engineering since 2021. He has massive shoes to fill.
Apple is welcoming Ternus into the top job right before the stock market typically has its worst month of the year. But don't panic and sell your stake. Instead, stay focused on the long term.
Here's what investors should know.
Image source: The Motley Fool.
Here comes September sadness
The S&P 500 index (^GSPC -0.21%) has generated notable wealth for patient and diversified investors over time. Its average annual total return is about 10%. This means a $10,000 starting capital outlay, sitting idle without any further cash infusions, would be worth $174,000 in 30 years. No one will argue with that outcome.
However, the market has never risen in a straight line, and there will be plenty of times when investors won't be enjoying gains. To own stocks, you need to be able to handle the volatility along the way. This is timely advice to remember right now.
There's something called the September effect that investors might want to get familiar with. September, on average, is the worst month of the year for stocks. During the 10 Septembers from 2016 through 2025, the S&P 500 index posted an average return of negative 1.3%.
Of course, this doesn't guarantee that the market will decline during the next month. In five of those 10 years, the S&P 500 actually gained ground.
Long-term investors should be unfazed
What is known to be the worst month in the stock market is awaiting John Ternus as he becomes CEO of Apple. He's taking control of one of the world's most dominant businesses after two highly successful leaders in Cook and Jobs called the shots.
Leadership changes don't always go smoothly. And as mentioned, the S&P 500 index has a rough track record in Septembers.
Should Apple shareholders dump their holdings? That might seem like a sound play. But it's not the right move to make.

NASDAQ: AAPL
Key Data Points
Ternus isn't an external hire. He has been with Apple since 2001. There are few people on Earth who have as deep an understanding of this business as he does. This significantly reduces the risk of him making any operational or strategic blunders.
Additionally, Ternus has been in his current role on the executive team for five years. He oversaw the numerous new devices Apple launched this decade. He knows precisely what variables drive the company's success in hardware and product development.
I believe it'll be business as usual for Ternus. He doesn't have to reinvent the wheel here. Apple has become one of the most successful companies ever. There's no need to mess with what's been working for so long.
And clearly, the iPhone -- Apple's cash cow product -- is working. Over the first three quarters of its fiscal 2026 (a period that ended June 27), iPhone sales jumped 22% year over year. Demand for the latest iPhone 17 family has been impressive, despite the fact that many consumers are still waiting to buy until there's an artificial intelligence update for Siri.
At its September event, Apple is expected to unveil a foldable iPhone, among other announcements. As is typically the case, this should drum up renewed interest in the brand and shine a spotlight on its innovation prowess. Ternus knows how important it will be to start his tenure on the right foot.
And on the topic of September being a negative month historically for the S&P 500 index, long-term investors shouldn't be fazed. Assuming you have decades until it's time to retire, a single month's performance will have little impact on how your portfolio will do. The best investors stay the course.





