Apple appears set to capitalize on an increase in popularity of its already-popular line of computers and is rumored to be planning to release a thinner version of its MacBook laptop.

The production of components for these thinner MacBooks evidently has already begun, according to Taiwanese suppliers and reported by Digitimes. The thinner MacBooks could be on sale as early as the fourth quarter of 2014, but more likely would be released in 2015.

The suppliers wouldn't reveal the expected thickness of the new machines, and Apple is silent as well. The current MacBook Air model is between 0.3cm and 1.7cm thick, while the MacBook Pro with Retina is 1.8-cm thick. The 13.3-inch MacBook Pro is 2.4cm thick, but is expected to have run its course by the end of this year.

The thinner MacBook rumors have emerged at a period of growth for Apple's line of Macs. In the second quarter of 2014, Apple sold 4.41 million Macs, up 7 percent from the first quarter and up 18 percent from the second quarter of 2013. Of those sales, 80 percent were MacBooks.

Internet rumor mill Mac Rumors claims that the new MacBook will be 12 inches and come with a Retina display. It's not clear if the 12-inch model will succeed the MacBook Air or if it will join the 11- and 13-inch models.

Previous rumors claimed that Apple would start production of the thinner MacBook this quarter, but that has not been confirmed. The machine is said to feature a new cooling system and a trackpad without buttons, similar to the current MacBook Airs.

If the new MacBook is to come out in the fourth quarter or early in 2015, Apple may reveal the computer at its October event. The company is expected to unveil the iPhone 6 on Sept. 9