Shares have had a bad month. Apple has had a worse one.
Shares from the iPhone manufacturer were lower on Tuesday afternoon after comments Monday from President Trump suggesting that tariffs could be placed on the company's units imported from China.
In the last month, Apple's share has fallen 20 percent, which puts it at pace for the worst month since the financial crisis.
The tumbling has sharpened around $ 230 billion of Apple's market value, placing it close to losing its position as most valuable listed company to Microsoft.
The two companies have competed since the mid 1970s, when both were founded. Microsoft dominated its rival in the 1990s and drove the popularity of its Windows operating system to become the largest listed company by the end of the decade. During that time, Apple fled to break.
But the dynamic reversed. Microsoft's shares and market value stagnated for more than a decade after the dot-com bust. Driven by the release of products like iPod and later iPhone, Apple's shares marched higher.
In 2010, Apple's market value passed Microsofts, and the gap between the two continued to grow and reached as much as $ 400 billion by 2015. As recently as a month ago, Apple was worth about $ 250 billion more than Microsoft.
In recent weeks, investors have grown more concerned with iPhone sales. A number of Apple suppliers are cutting their financial outlook for the quarter, suggesting that there may be weaker demand for the latest models of the phone than expected. Last year, sales of iPhones accounted for nearly 60 percent of Apple's revenues.
Microsoft has gone a lot better during the November stock market route. Last month, Microsoft reported better than expected earnings driven by continued rapid growth in its commercial cloud computing business. Its shares are up about 1 percent this month.