Three months after its release, reports suggest that the Samsung Galaxy S5's sales are significantly below the company's targets. Total sales of the device are believed to be around 12m units - Apple's iPhone 6 sold 10m in the first week.

Optimistic forecasters increased production of the phone by 20 percent, relative to the S4. Going on today's report, that phone sold 25 percent more units over the same time period. The story broke in The Wall Street Journal - they suggest that unsold stocks of the phone are piling up in Samsung's warehouses.

This news is not a total surprise, the poor performance of its high-spec phones was one of the main causes of the company's disappointing earning figures in the last quarter. Samsung has already announced a shake-up of its mobile strategy, planning to streamline its offering, and to focus more of its efforts on mid-range smartphones. 

Sales are said to be down 50 percent in the Chinese market where they are losing market share to the iPhone 6 at the top-end and indigenous companies like Xiaomi, Lenovo and Huawei in the entry and mid-level markets.

Some of the success of the S4 was down to Apple's decision not to make the iPhone 5's screen bigger, a trend that Apple has now embraced.

The Wall Street Journal is reporting that the poor sales could lead to a leadership shake-up in the South Korean company. J.K. Shin is co-CEO and the leader of the mobile department. The New York paper says that the company is considering taking away his executive status and putting him solely in charge of the mobile division. Co-CEO B.K. Soon, who is in charge of Samsung’s successful home appliance and TV businesses would supervise the mobile division.