Concerning the iPhone 5C and the iPhone 5S , Apple did not foresee the rate of sales between the products .
Apple admitted that it had failed to anticipate the sales ratio between the iPhone 5C and the iPhone 5S , leading to an overstocking of the 5C and shortages of the 5S.Six months after the release of the iPhone 5S , on March 25 , 2014 , Apple announced that sales of the iPhone brand has crossed 500 million units .