Two of Warren Buffett's largest stock holdings have been absolutely creamed in the markets recently, leaving the Oracle of Omaha down about $2.4 billion in just the past seven days.

Is Coca-Cola losing its fizzle?
Last Wednesday, shares of Coca-Cola Company (NYSE:KO) opened the trading day at $43. By the close of trading last night, those shares were down about 6% to $40.68. 

Buffett owns 400 million shares of Coca-Cola, according to Berkshire Hathaway's (NYSE:BRK-A) (NYSE:BRK-B) most recent filings with the SEC. Therefore the math works out to a loss of over a billion dollars.

Coke's decline came as a result of a disappointing third-quarter earnings report. The world's largest soda brand reported flat volume sales, with declining revenue and earnings. Company management also announced a new plan to cut upwards of $3 billion in annual costs by 2019.

KO Price Chart

KO Price data by YCharts

The results beat Wall Street expectations, but investors ignored that short-term win and instead sold off the stock on concerns over its long-term growth potential.

IBM drops over 11%
Buffett's fourth-largest holding, IBM (NYSE:IBM), had an even worse week than Coca-Cola. Big Blue fell about 11% over the week ending with the closing bell on Tuesday night, dinging Buffett for a cool $1.4 billion paper loss.

Like Coca-Cola, IBM's fall was precipitated by a tough third-quarter earnings report. The company reported a 17% decline in profits from the second quarter and continued revenue declines amid attempts to reshape itself from a hardware company to a software and services business.

IBM Price Chart

IBM Price data by YCharts

Despite a few glimmers of hope in the company's software businesses (the cloud server business saw revenues jump 50%), management was forced to back off its previous goal of $20 in earnings per share by 2015. The company will update its 2015 EPS target in January, but the market is obviously not optimistic.

A valuable and Foolish lesson
Coca-Cola and IBM are both facing long-term shifts in their businesses. Coke is seeing a stagnation of growth after 20 years of near constant increases in volume and revenue. The company is now shifting to maximizing profits by cost-cutting -- any growth will now come on the periphery.

Likewise, IBM is attempting to reinvent itself as a nimble, service-first company. It is divesting essentially all of its hardware businesses and investing that cash into cloud technology, Watson-like big data solutions, and other next-generation technologies.

Buffett Fool Flickr

Does this look like a man concerned with quarterly market gyrations to you?

Here's the thing, though, about Warren Buffett -- the $2.4 billion he lost in these two stocks over the last week won't cause him to panic or change his game plan. Buffett isn't in these stocks for quarter-to-quarter performance -- he's in it for the long term. He's owned Coca-Cola since the 1980s!

As we save and invest throughout our working careers, we must continue to keep our eyes on the long-term prize, just like Buffett.

That means patience and calm. It means not checking the market averages every day. It means periodically rebalancing and reassessing risk in your portfolio. It means working hard to minimize fees, expenses, and unnecessary tax obligations. There's a reason Coca-Cola is turning its focus to cost-cutting -- it's a great, easy way to maximize your returns over the long term.

The market will go up, and sometimes it will go down. As long as we have a smart game plan and stick to it, we can rest easily as the market gyrates from quarter to quarter, just like I'm sure Buffett is sleeping easily this week.

Jay Jenkins has no position in any stocks mentioned. The Motley Fool recommends Berkshire Hathaway and Coca-Cola, owns shares of Berkshire Hathaway and IBM, and has options on Coca-Cola. Try any of our Foolish newsletter services free for 30 days. We Fools don't 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.