Corporate travel and expense company Navan said on Friday it is targeting a valuation of up to $6.45 billion in its U.S. initial public offering. The Palo Alto, California-based firm plans to raise $960 million by offering 36.92 million shares priced between $24 and $26 apiece. Navan plans to list its shares on the Nasdaq under the symbol "NAVN". U.S. IPO activity has rebounded in recent months amid easing trade policy uncertainty and reduced market volatility, reflecting improved investor