How about Energy World Corporation on Wednesday? Stock in the Hong Kong-based natural gas business climbed 12.7 per cent during the day’s trading, the biggest jump on the ASX 200, and all without a statement to the market or any other clear reason for its take-off. After scratching his head, Listings Compliance adviser Adam Russo wrote to Energy World to ask about it. “We have noted a change in the price of the company’s securities from $0.465 on 17 July 2013 to a high of $0.62 today," Russo wrote, before asking if, perhaps, there was something to be announced that might clear things up. At 3.26pm, going off the fax, an answer was given by Energy World’s executive director, Brian Allen. “Beats me," was the nub of his response. Someone unlikely to be writing in to complain was Capital Group Companies. The giant investment manager increased its stake from 5 to 6.1 per cent, in May. It’s a volatile industry.