Peter will provide more details about all of this in a moment. We appreciate the input that so many of our shareholders have provided us on how best to deploy our cash. We will review our cash allocation strategy each year, and we will continue to invest confidently in the business to bring great new products to market, strategically deploy capital in our supply chain, our retail stores and our infrastructure, and make acquisitions to expand our capabilities. We will be disciplined in what we do, but we will not underinvest.
I'd now like to turn the call over to Peter to discuss the details of the March quarter.
Peter Oppenheimer - SVP and CFO: Thank you, Tim. We are pleased to report the results of our second fiscal quarter. We established new March quarter records for iPhone and iPad sales and new all-time record for iTunes sales, leading to Apple's strongest March quarter revenue ever.
Revenue for the quarter was $43.6 billion, compared to $39.2 billion in the year ago quarter, an increase of $4.4 billion, or 11%, and $600 million over the high end of our guidance range. The year-over-year revenue increase was fueled primarily by strong growth in iPad and iTunes sale, as well as continued strong revenue from iPhone and Mac.
Operating margin was $12.6 billion, representing 28.8% of revenue. Net income was $9.5 billion, translated to diluted earnings per share of $10.09.
As for the details of the quarter, I'd like to begin with iPhone. We sold 37.4 million iPhones compared to 35.1 million in the year-ago quarter, and increase of over 2.3 million or 7%. We ended the quarter with about 11.6 million total iPhones in channel inventory, a sequential increase of about 1 million iPhones and we ended the quarter within our target range of four to six weeks of iPhone channel inventory.
Based on research published earlier this month by comScore iPhone garnered the number one spot in the U.S. smartphone market for the three-month period ended in February with 39% share, up from 35% in the previous survey period. And in Japan, IDC Japan announced that iPhone gained the number one position for all of calendar year 2012 as well as for calendar Q4 2012 in both handsets and smartphones. This is also the first time a non-Japanese company has achieved the number one spot for an entire year.
In addition, Apple was ranked number one in Nikkei's 2013 Japan Brand Survey, achieving the top spot for the second year in a row which is unprecedented for a non-Japanese company. Around the world based on its latest published estimate, IDC ranked iPhone number one or two in smartphone sales in over half the countries IDC track.
A recent study by Kantar measured a 95% loyalty rate among iPhone owners, substantially higher than the competition, and iPhone remains top in customer experience. Last month, we were very pleased to receive the number one ranking in smartphone customer satisfaction from J.D. Power and Associates for the ninth consecutive. Business around the world continue to scale iPhone across their work forces. Globally, nearly 30,000 companies are developing and iOS apps for corporate use by their employees. Cisco's Bring Your Own Device program across 80 countries has resulted in a 50% increase in the number of iPhones connecting to its corporate network in the past year. GlaxoSmithKline has developed more than 50 in-house iOS apps to support the thousands of iPhones and iPads connecting to its corporate network. Other companies, such as AXA, Nordstrom, Eaton Corporation and Takeda Pharmaceuticals, are supporting thousands of iPhones and are continually adding new in-house apps to better serve customers and help employees work more efficiently.