When scuffles broke out among stressed Foxconn workers on an iPhone 5 assembly line last year, it sparked fears among Apple devotees waiting for the gadget and investors in the world's largest contract manufacturer waiting for higher margins.
In the end, Foxconn, also known as Hon Hai Precision Industry, delivered – tens of millions of phones, record high annual revenue and, in the last quarter of 2012, its highest operating margins in three years.
Since then new concerns have emerged about slowing growth at Apple, Foxconn's main customer, while workers and recruiters at some of the Taiwanese group's factories say the company has slowed hiring and asked workers to do less overtime.
Further slowdowns at the U.S. group will pinch Foxconn's sales, especially if the new phones Apple is expected to reveal soon do not sell well or are so low-priced as to do significant damage to Apple's own margins, as some analysts fear, given the disappointing sales of the iPhone 5.
However, in spite of these concerns, analysts expect Foxconn's recent progress on profitability to be sustained as it maintains its key role in Apple's supply chain and outstrips its PC-focused competition.
"The biggest change in terms of Hon Hai in the course of last year is . . . its margin profile actually improved," says Jenny Lai, head of Taiwan research for HSBC.
(Read More: Bad Sign for Tech: Idle FoxConn Factory)
In one year, the company tripled its operating margin – from 1.1 percent in the fourth quarter of 2011 to 3.7 percent for the fourth quarter last year.
It also recently picked up one prominent new customer in Google, which placed an order, albeit a tiny one, for Foxconn to make its Google Glasses at a factory in California.
By contrast, most of its smaller competitors, particularly other Taiwanese assemblers Quanta, Compal and Wistron, recently reported that their margins had fallen as their core PC businesses slid and they struggled to find new customers with greater exposure to the growing mobile device segment.
One big factor underpinning Foxconn's recent recovery is the conclusion of one of the biggest migrations yet of manufacturing capacity. The company started in the 1980s in Shenzhen, near Hong Kong. Since then, and starting as early as 2008, rising wages prompted the company to build new facilities closer to the hometowns of its mostly migrant workforce, in inland cities such as Zhengzhou, where the iPhone 5 is made.
(Read More: Apple's Apology Wins Respect of China Media)
Now, the company's employees are thought to be split nearly evenly, with half a million at its inland factories and half a million at its factories on China's eastern coast including Shenzhen.