 The authors of a recent study on insider trading have taken a new, financial spin on the classic thought experiment that asks whether a falling tree makes any sound in an empty forest. Looking at how corporate insiders might use confidential information to make trades, they ask if executives of publicly traded companies meet with investors and no one from the public is around, does the information exchanged still influence the stock market? The results are striking. The authors showed that, leading up to a private meeting, investors traded stocks based on the belief that the meetings would reveal positive information. These run-ups generated an average of 11 million U.S. dollars per firm. The authors gathered this insight using the Shenzhen Stock Exchange, which offers unusual data. It requires listed companies to report the dates and minutes of their private meetings with investors, giving researchers a sneak peek at insider information. The authors mined this data and compared it with trading patterns to determine the impact of this privileged information. On average, each company held five private meetings. 20% of these meetings could be linked to disclosed insider trading activities. This may not sound like a lot, but overall, the trades, some 12 billion U.S. dollars over two years, represent nearly two-thirds of the value of all insider trading among Shenzhen Stock Exchange listed companies during that time. Given these findings, the authors ask whether developed markets like the U.S. should follow the lead of Shenzhen and require public records of private meetings. Maybe, they argue, it's time to allow everyone to trade on this information, not to condone insider trading, but to level the investment playing field.