July 15 (Reuters) - Phillips Edison & Co Inc"s (PECO.O) shares opened flat at $28 in their Nasdaq debut on Thursday, giving the owner and operator of omnichannel shopping centers a valuation of more than $3 billion. The real estate investment trust (REIT) on Wednesday raised $476 million through the sale of 17 million shares in its initial price offering, in which it had aimed to sell the stock between $28 and $31 each. The listing comes at a time when brick-and-mortar retailers are still recovering from the impact of the COVID-19 pandemic, which could in turn weigh on REITs like Phillips Edison. The company"s portfolio is chiefly focused on grocers who use an omnichannel sales approach that seeks to offer customers a uniform experience, whether they are shopping online or at physical stores. Phillips Edison, which was founded in 1991 and purchased its first shopping center in Virginia a year later, currently counts Trader Joe"s, Kroger Co (KR.N), Walmart Inc (WMT.N), Walgreens Boots Alliance (WBA.O) and Starbucks Corp (SBUX.O) among its more than 5,000 tenants. The REIT was born in its present form after Phillips Edison Grocery Center REIT I Inc acquired Phillips Edison Limited Partnership"s real estate assets and asset management business in 2017. Morgan Stanley, BofA Securities and J.P. Morgan are the lead joint book-running managers for the offering.