Carrier IQ Inc., a Mountain View company that’s come under fire in recent weeks over concerns about tracking software installed on 140 million smartphones, now faces 51 proposed class actions in state and federal courts.

Almost a third of the proposed class actions — 14 — have been filed in the Northern District of California, and name codefendants Apple Inc., AT&T, HTC Corp., Samsung Electronics America and LG Electronics along with Carrier IQ. One suit in California state court names Google Inc. as a defendant.