The renewed strength of the retail sector was on display again on Thursday after a slew of companies reported sales growth, likely a reflection of an improved economy and higher consumer sentiment.

The string of strong earnings come as nearly all industry sectors invest heavily in e-commerce to better compete with Amazon. Despite the growth, however, investors continue to have concerns over the capital required to support those online platforms, as well as the ability of traditional brick-and-mortar retailers to expand that business.