3i Group shares dropped about 7% to 2,060 pence on Monday, despite the company launching a £750 million buyback and cancelling 701,317 shares. The stock traded well below its reported net asset value of 3,030 pence per share. Investors focused on slowing sales growth at Action, 3i’s main asset, as like-for-like sales rose just 2.4% in the year to May 10.