Fiber laser and amplifier maker IPG Photonics Corp. on Tuesday set its planned initial public offering at 9 million shares for between $13.50 and $15.50 apiece, according to an amendment to an offering document filed with the US Securities and Exchange Commission. The company will offer 6.2 million shares and selling stockholders will sell another 2.8 million shares, the SEC said. The underwriters, led by Merrill Lynch & Co. and Lehman Brothers, will have the option to buy another 1.35 million shares to cover over-allotments. IPG, based in Oxford, Mass, intends to list its stock on Nasdaq under the symbol "IPGP." The company announced an initial public offering of up to $130 million in common stock in August. (See also "IPG Photonics Files for IPO.")