The price of the iPad Mini, whose screen is roughly two-thirds of the full-size model, is higher than competing small tablets. The Kindle Fire made by Amazon.com Inc. starts at $159.
Apple Inc.'s shares fell $20.67, or 3.3 percent, to close at $613.36. The stock is down 13 percent from the all-time high of $705.07 touched on Sept. 21.
Amazon's stock, meanwhile, inched up less than 1 percent to $234.31. Shares of Google Inc., another tablet competitor, also climbed less than 1 percent, to $680.35.
Barnes & Noble Inc., which makes the Nook tablets and e-readers, climbed 88 cents, or 6.1 percent, to $15.32. The stock has traded in the 52-week range of $9.35 and $26.