Apple has announced Chief Financial Officer Peter Oppenheimer will retire at the end of September, according to Reuters.

Oppenheimer's successor will be Corporate Controller Luca Maestri, according to the iPhone maker.

Oppenheimer, 51, joined Apple in 1996 and has been CFO since 2004. He will start handing over control to Maestri, who joined in 2013 from Xerox Corp, this June.

"When we were recruiting for a corporate controller, we met Luca and knew he would become Peter's successor," Chief Executive Tim Cook said recently, according to Reuters.

Maestri, 50, spent 20 years at General Motors, and before joining Xerox, he was CFO of network equipment maker Nokia Siemens Networks.

"The transition doesn't come as too much of a surprise to us as Mr Maestri left his position as Xerox's CFO to become Apple's corporate controller, which we felt was an indication that there must be an eventual path to CFO," Wells Fargo Securities analyst Maynard Um said, according to Reuters.

Oppenheimer was named to the board of Goldman Sachs Group on March 3, according to Reuters.

The CFO said he is planning on using some of his free time to complete his pilot's license.

Cross Research analyst Shannon Cross believes Oppenheimer's decision had nothing to do with the Goldman Sachs announcement.

"There is nothing there. This was absolutely a 100 percent planned transition," Cross said to Reuters.

Cook said that Apple's revenue has increased to $171 billion from $8 billion during Oppenheimer's tenure as CFO.

Additionally, Apple shares were up 0.7 percent at $531.22 in early trade, according to Reuters.

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