[Top 20 US stock turnover: KeyBanc said Apple's stock price is near an all-time high, but sales growth may slow] No. 3 Apple closed up 0.73%, trading $9.113 billion. KeyBanc Capital Markets downgraded Apple shares to "sector perform" from "overweight," saying the stock's valuation is near an all-time high but sales growth could slow. Analysts at the bank wrote in a note that the iPhone upgrade cycle is challenging amid slowing consumer spending and that "sales in the U.S. market could struggle." In addition, "Expectations of further accelerated growth in international markets may be too aggressive."