Due to the popular and strong sales of iPhone 5S, Susquehanna Financial Group predicted that Apple's (AAPL:NASDAQ) stocks may go up to $650.

Susquehanna Financial Group's Christopher Caso gave Apple a positive rating and raises his price target to $650 from $625. The reason for the increase is the sudden shift of production from iPhone 5C to iPhone 5S. This "implies a much stronger mix than originally anticipated," benefiting both revenue and margins," he said.

The demand on iPhone 5S is beneficial on the revenue and gross margin of Apple in the fourth quarter. According to the report of the financial group, iPhone builds are running in the 52-54 million range. Thus, Mr Caso raises his estimate for the current quarter, Apple's fiscal Q1, to $57.1 billion and $14.02 per share from a prior $56.6 billion and $13.54.

Right now, Apple shares fell $4.22, or 0.8%, to close at $550.77, recovering from the lowest level of the session, $538.80. The slight slump could be due to the company's inability to produce an announcement of a formal deal to sell the iPhone with China Mobile.

Mr Caso also said that iPhone 6 announcement next year is of vital importance for the company. Since iPhone 5S is doing well in terms of sales and is doing better than expected, it releases the pressure of releasing the device early. Mr Caso thinks that iPhone 6 will arrive either in June or July. He said that it is important that Apple will launch a new iPhone earlier than usual as it needs a device to reignite the sales.

Previous rumours pointed to an earlier release date in the first quarter of 2014, probably around March. However, other speculations started to emerge saying that the next iPhone will be released later next year. Apple may wait for a full year to maximize the profits of the current iPhones.

According to rumours, iPhone 6 will sport larger screen display with a size between 4.8 to 6 inches. The 64-bit A7 processor, M7 graphics chip and the fingerprint sensor found in the iPhone 5S will most likely be retained in the next iPhone. Moreover, new patents hinted that iPhone 6 may include a curved screen display and a refocusable light camera although Apple has not confirmed any of the flying rumours.