(Reuters) - Pattern is seeking a valuation of up to $2.64 billion in its initial public offering in the United States, the e-commerce firm said on Wednesday, in a further sign of resurgent demand for new listings. After an April slowdown tied to tariff jitters, improved trade prospects and strong investor demand for IPOs restored confidence in the market. The Lehi, Utah-based company and some of its existing shareholders are offering 21.4 million shares, priced between$13 and $15 apiece, to raise as muc ...