Berkshire Hathaway (BRK.A -0.76%) (BRK.B -0.69%) CEO Warren Buffett is easily one of the greatest investors of our generation. He's doubled up the annualized total return, including dividends paid, of the S&P 500 since becoming CEO in 1965 (as of Dec. 31, 2022), and he's overseen an aggregate return in his company's Class A shares (BRK.A) of 4,365,810%, as of the closing bell on Aug. 25, 2023.

What makes the Oracle of Omaha an investor favorite is his willingness to share what's made him successful. It also doesn't hurt that Berkshire Hathaway is required to disclose its holdings each quarter via a 13F, which has allowed investors to ride Buffett's coattails to significant gains over a span of nearly six decades.

A jubilant Warren Buffett at Berkshire Hathaway's annual shareholder meeting.

Berkshire Hathaway CEO Warren Buffett. Image source: The Motley Fool.

At the moment, the $352 billion investment portfolio Warren Buffett oversees holds positions in more than 50 securities. Among these 50-plus investments are two screaming buys for the month of September, as well as one pricey market leader that would be best avoided.

Warren Buffett stock No. 1 that's a screaming buy in September: Visa

Although Wall Street's major stock indexes are still well below their record-closing highs, the top Buffett stock to buy in September is a company that's well within striking distance of its all-time high: payment processor Visa (V -0.23%).

The biggest headwind patient investors will ever contend with while owning shares of Visa is that it's a cyclical company. If U.S. and/or global economic growth slows or shifts into reverse, it's only logical to expect consumer and enterprise spending to slow. Since Visa generates its revenue and profits from merchant fees, it counts on a growing domestic economy and thriving international landscape to thrive.

But there's a key advantage to being cyclical that a lot of investors either overlook or misinterpret: Namely, U.S. economic expansions and recessions aren't mirror images of one another. Whereas all 12 U.S. recessions post-World War II have lasted just two to 18 months, periods of expansion have almost always extended for years. A company like Visa is disproportionately benefiting from these long-winded expansions.

Another reason investors won't have to worry about Visa is because of the company's focus on payment facilitation. While some of its peers have chosen to operate on both sides of the aisle -- i.e., process payments and lend to consumers via credit cards -- Visa is strictly a payment processor. This gives Visa no direct liability during economic downturns when credit delinquencies creep up and charge-offs/loans losses occur. Not having to set capital aside to cover potential losses makes bouncing back from downturns faster than most of the financial sector.

As of 2021, Visa was the undisputed leader in credit card network purchase volume in the United States. Among the four major payment processors, Visa's 52.6% share of the U.S. market was about 29 percentage points higher than its next-closest competitor. Its dominance in the world's top market for consumption (the U.S.), coupled with most emerging markets still being underbanked, provides a sustained runway for high-single-digit or low-double-digit annual sales growth.

Lastly, investors have to go back to 2018 to find the last time Visa was this inexpensive on a forward-earnings basis -- 24 times Wall Street's consensus earnings per share in 2024.

Warren Buffett stock No. 2 that's a screaming buy in September: General Motors

The second Warren Buffett stock that's a standout buy in September is one of the holdings currently being pared down by Buffett and his team: auto stock General Motors (GM 0.48%).

Two headwinds appear to be weighing on GM at the moment. The first, which is similar to Visa, is the growing expectation of economic weakness in the U.S. or aboard. Automakers are highly cyclical, which means economic downturns almost always result in fewer new vehicles being sold.

The other big concern for General Motors is the price war Tesla kicked off earlier this year in the electric vehicle (EV) space. Though price wars can be good for the consumer, they're almost always bad news for the automotive margins of manufacturers.

However, Tesla's price war hasn't put a dent into GM. On the contrary, CEO Mary Barra and her team have kept a close eye on production levels to ensure that inventory doesn't grow out of hand. As a result, General Motors' automotive free cash flow forecast for 2023 was recently increased by a median of $1.5 billion to a range of $7 billion to $9 billion this year. 

In addition to GM's internal combustion engine vehicles being overwhelmingly profitable at the moment, the company is spending aggressively on its electrified future. General Motors anticipates spending $35 billion through 2025 on EV, autonomous vehicle, and battery research. The goal is to be pacing at least 1 million EVs produced annually in North America by the end of 2025.

GM's ability to secure EV share in China is another catalyst. Through nearly a dozen joint ventures in China, General Motors already has established infrastructure in place, along with well-known brands, which can allow it to gobble up share in the world's No. 1 auto market. 

A forward price-to-earnings ratio of 4.7 more than bakes in any near-term headwinds and makes General Motors a no-brainer buy.

Two excited children playing with display iPhones in an Apple Store.

Image source: Apple.

The Warren Buffett stock to avoid like the plague in September: Apple

However, not all of Warren Buffett's holdings are worth buying at the moment. Though what I'm about to say will be considered blasphemous by many -- including the Oracle of Omaha himself -- the Buffett stock to avoid like the plague in September is none other than tech stock Apple (AAPL -0.35%).

Is Apple a bad company? Absolutely not. It has an incredibly loyal customer base and a widely recognized brand, and the company has generated $113 billion in operating cash flow over the trailing four quarters ended July 1, 2023.

Apple is also in a class of its own when it comes to capital-return programs. It's doling out more than $15 billion annually to its shareholders in dividends and has repurchased around $600 billion worth of its common stock since commencing its buyback program in 2013. Share repurchases of this magnitude have undoubtedly helped push Apple's earnings per share higher.

But the one aspect about Apple that's made it such a great company to own is its sustained growth. As of this moment, the company's growth engine has completely stalled. Wall Street's consensus is for the largest publicly traded company in the U.S. to see its sales and profits decline by a low-single-digit percentage in fiscal 2023 (Apple's fiscal 2023 ends on Sept. 30, 2023).

Not much seems to be working for Apple at the moment. iPhone sales are down nearly $6.1 billion through the first nine months of fiscal 2023 when compared to the same period a year earlier. The company had plans to expand production of iPhone 14 but was met with lukewarm demand for the product following its launch. Meanwhile, sales of Macs are down 24% through nine months. 

Furthermore, a report from the Financial Times suggests Apple is cutting production of its Vision Pro mixed-reality headset from a purported 1 million units to just 400,000 in 2024. Apple relies on innovation and growth from existing products. In fiscal 2023, it's not performing in either respect.

After consistently trading at a forward price-to-earnings ratio of 10 to 15 from 2013 through 2018, investors would have to pay 27 times forward earnings to own shares of Apple today. That's incredibly pricey given its lack of growth, and all the more reason to avoid Warren Buffett's largest holding like the plague in September.