 Shares of Cinemark Holdings Inc. CNK, -0.15 dropped 1.8 in premarket trading Friday, after the movie theater operator swung to a surprise loss, while revenue more than doubled to beat expectations as attendance nearly tripled. The net loss was 73.4 million, or 61 cents a share, after net income of 142.4 million, or 1.19 a share, in the year-ago period. 