Samsung warned that its smartphone sales weren't that great this spring, and now we have the numbers to show just what the company meant. IDC estimates that Samsung's smartphone shipments saw a rare year-over-year drop in the second quarter, taking it from a lofty 32.3 percent market share down to 25.2 percent. That's still enough to give it a comfortable lead, but a shock for a company which is used to growth. The cause, analysts say, is the rapid rise of Chinese brands that cut directly into Samsung's low-end business. Huawei claimed 6.9 percent of the smartphone space after doubling its shipments, thanks in part to heavy discounts on phones like the Ascend P7; Lenovo jumped to 5.4 percent on the back of both budget phones at home as well as rapid expansion abroad.