Demand for Apple’s latest products is as strong as ever, it would seem.After reportingsales of 51 million iPhones and 26 million iPads during the lucrative holiday quarter, as a result Apple’s key contract manufacturers –FoxconnandPegatron– are seeing a nice rise in their earnings, too.

Pegatron, the primary manufacturer of the iPhone 5c and iPad mini, last week reported a cool 22 percent annual rise in earnings attributed to strong demand for mobile products. Apple is responsible for as much as 40 percent of Pegatron’s business so the manufacturer’s fortunes are closely tied to the iPhone maker’s.

iPhone 4 promo vide (manufacturing process 001)

As for Foxconn, they reported a 13 percent rise in net profit today. Foxconn is the world’s top contract manufacturer and Apple’s lead supplier…

According to The Wall Street Journal, Foxconn said Friday its net profit last year rose thirteen percent,“helped by an increase in iPad and iPhone sales”, as it also announced a $90 million investment in new manufacturing and software development operations.

iPhone 6 concept (ConceptsPhone 001)

Taiwan-based Foxconn, also known as Hon Hai Precision Industry Co., earns more than 40 percent of its revenue from Apple. The firm recentlypartnered with Google on production line automationusing robots that run the Internet giant’s upcoming robotic operating system for manufacturers.

During a recent event marking Foxconn’s 40th anniversary, its Chairman, co-founder and CEOTerry Gou saidhis company was exploring the possibly of opening a large display plant in the United States.

iPhone 5c (Manufacturing 001)

Foxconn is also though to havelanded orders for the next iPhone(s), with production trial runs of the handset using sapphire as a display glass cover having started recently.

As for Pegatron, The Wall Street Journal reported last week that the firm’s results were underpinned by demand from Apple:

The earnings boost posted Monday accompanied strong growth of Pegatron’s revenue from smartphones and other communications products, even as its overall revenue fell from a year earlier amid sluggish sales of its core personal-computer business.

Their operating margin, however, is razor-thin (thanks to Apple), having increased from just 1.6 percent a year ago to 1.9 percent in the most recent quarter.

“Analysts said Pegatron has suffered from low operating margins in recent years partly because of a low yield rate as it began making products for Apple,”as per the report. Margins are bound to rise as Pegatron gathers experience building Apple product and improves its efficiency.

In addition to building theiPad miniand theiPhone 5c, Pegatron toomay have landed ordersfor large-screened iPhones, accounting for abouthalf of total output. The company could also start assembly work for Apple’s iPad Airand the all-in-one iMac desktop this Fall.

Foxconn and Pegatron’s stellar four-quarter results aside, contract electronic makers are about to experience a sharp drop in earnings: the first quarter has traditionally been a dry season as device vendors aren’t launching many products early in the year.