In just two years, Apple Inc's (NASDAQ:AAPL) debt has jumped from $0 to $47 billion, making it one of the biggest borrowers on Wall Street. While the company has invested alongside its debt to establish a seemingly conservative position, taking on $15 billion or more of debt annually may not be sustainable. 

Here are few of the challenges Apple faces in its quest to return capital to shareholders. 

Jeremy Bowman owns shares of Apple. The Motley Fool owns and recommends Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.