Nymex ( NMX) fell after a Merrill Lynch analyst said the commodities exchange's current valuation is unreasonably high. The analyst began coverage of the stock with a sell rating. Shares were down $4.52, or 3.6%, to $119.49. Ace ( ACE) dropped after the insurer announced it had bought Peru's Altas Cumbres Life Insurance, a company with more than 700,000 customers. Terms weren't disclosed. Shares were down 88 cents, or 1.5%, to $59.47. American Capital Strategies ( ACAS) slipped after the building development company said it will sell 6 million shares in a public offering. The underwriters on the deal will sell 2 million of the shares, with the remainder being sold by the company. Shares were falling 46 cents, or 1%, to $46.23. Wintrust Financial ( WTFC) jumped on an upgrade by a Piper Jaffray analyst to outperform from marketperform. Shares were gaining $1.36, or 2.9%, to $49.56. Wachovia ( WB) rose after an analyst with Credit Suisse upped its rating to outperform from neutral. Shares were adding 51 cents, or 0.9%, to $57.32.