Investors often think of the start of autumn as a time of increased volatility for the market due to a phenomenon known as the "September Effect," a historically-verifiable trend in which the market tends to underperform compared to other months out of the year. While it's unclear what exactly causes the September Effect—possible explanations range from post-summer portfolio realignment to a shift toward bond activity to a psychological effect, among others—this time of year undoubtedly makes many investors a bit more nervous than usual.

Given the speculation surrounding the Federal Reserve's decision about whether to reduce interest rates, this is particularly true this year.

To keep investments as stress-free as possible during the fall, consider companies that have unassailable fundamentals, a strong performance record, and business models prepared to ride out short-term seasonal fluctuations in the market.

GigaCloud Technology: B2B Industry Growth Prospects, Share Buyback Plan

GigaCloud Technology Inc. (NASDAQ: GCT) provides B2B ecommerce services for international shipping and logistics, an often-overlooked industry that is estimated to grow at a CAGR of almost 14% for the next several years as businesses navigate moving between physical and online presences. GigaCloud reflects this with an online marketplace that has grown its seller base and transaction volumes.

GCT shares have shed more than half of their value since reaching highs in the low-$40 range earlier this year. But the company's fundamentals remain strong, suggesting the possibility that the last several months of declines may be an outlier and that shares may reverse course and trend upward once again.

Revenue in the most recent quarter more than doubled year-over-year while net income surged by nearly 47%. Better yet, the company is able to grow its top and bottom lines while maintaining strong gross profit improvement of 89% as well. A forward P/E ratio of 6.0 is lower than many rivals in the B2B space, suggesting that GigaCloud may be undervalued. And the firm has a comfortable surplus of money to spend, as evidenced by its recent announcement of a share-repurchase program.

UnitedHealth Group: Savvy Acquisitions, Sound Fundamentals

A blue chip company—one that is widely recognized and stable with the potential for long-term gains—is an excellent option for low-stress fall investing, and UnitedHealth Group Inc. (NYSE: UNH) is a leader among blue chips. The medical and insurance giant has a market cap of more than $550 billion and a rock-solid position in the diversified healthcare sector.

For a megacap firm like UnitedHealth, acquisitions have been a crucial means to expand into new markets and services. One area for investors to watch is the company's home health business, which received a boost last year when UnitedHealth completed its acquisition of LHC Group. It now intends to continue to grow this segment as it works toward acquiring Amedisys. Key acquisitions like this may prove key to UnitedHealth's ability to continue to increase its revenue and income.

UnitedHealth's fundamentals have remained strong despite the firm's large size. It has a history of impressive earnings and revenue growth, as well as a long tradition of paying out dividends.

Amazon: Web Services Point to Nearly 30% Upside Potential

Another major blue chip stock that provides both stability and growth potential is Amazon.com Inc. (NASDAQ: AMZN). As one of the best-known companies in the world, Amazon has unmatched brand recognition and a host of different business lines to allow it to keep generating sales regardless of external market conditions.

Key to Amazon's success in this moment is its Amazon Web Services segment, which is poised to continue to meet surging demand for cloud and other technologies linked to AI. This division generated more than $26 billion in revenue in the second quarter alone, an increase of about 19% year-over-year despite the firm already having a dominant position in the space. This is likely a crucial reason why Amazon shares are up nearly 27% in the last year.

Based on optimism about Web Services, analysts have given Amazon an average price target of more than $222 per share, representing upside potential of a massive 29.8%. For a company that is so well-established to be able to continue to grow at that pace is unique.

Set and Forget Stocks

Low-stress stock choices for the fall allow investors to set these investments and then forget them while they work behind the scenes to grow over the long term. This makes them ideal for investors not interested in making regular portfolio adjustments or daily trades. Certainly, past performance is not a guarantee of future success, but each of these companies gives multiple reasons to suggest that it will remain attractive into the future.

Source MarketBeat