Bed Bath & Beyond stock plunged more than 18% after the company reported disappointing 2018 guidance last Thursday. Also last week, the credit-ratings agency Standard & Poor downgraded its bonds to the lowest level still considered investment grade, according to CNN Money. Retail experts say the biggest issue may be with Bed Bath & Beyond's stores — "Too many of Bed Bath & Beyond's stores — especially older ones — are a mess," Neil Saunders, managing director of GlobalData Retail, wrote in an email to CNBC.