Driving the spike is a SEC 13F filing from noted retail investor, Leonard Green and Partners. The company disclosed a stake of 990,000 shares worth of Bed Bath & Beyond. However, the position is not new and the filing shows that that company has been building the stake over the past year or even longer.
During that time, Leonard Green had filed for exemptions to disclose the information, which means the company made a confidential filing in order to build the position. So the eventual disclosure moved the stock to the upside.
The filing, which is dated as of March 31, also includes another confidential filing which has yet to be revealed.
—CNBC's Dominic Chu contributed to this report.