We examine the price query system used by the NZX to monitor compliance with its continuous disclosure regime. We focus on the proposition that "unexplained" price movements detected by the NZX's surveillance systems reflect speculative trading. Examining a sample of price queries where the companies responded with a "no news" announcement, we find evidence of significant abnormal returns immediately prior to the price query and smaller but significant partial reversal of abnormal returns immediately following the "no news" response. We interpret the absence of a full reversal to indicate that prices are based on information-based trading rather than speculative trading.