Remember that shareholders are in the stock because they expect some type of risk adjusted return. 5% is out because that's the risk free return. 7-10% can be gotten with lower risk by index investing. 15-20-30 we're starting to get into a range where the investor is willing to part with their stock given the risk they took on. 30% tends to be enough to get everyone to sell. If it was a hot, fast growing company, it would be higher - if it was possible to get everyone to sell at all.