Shoppers are spending but it may not last

Costco

New York( CNN Business) Retailers are preparing for the final sprint of vacation browse as warning signs flash about 2019.

Shares of retailers like Target( TGT ), Costco( COST ), Kohl’s( KSS ), Nordstrom( JWN) and Tiffany( TIF) have fallen sharply in the past few weeks as expenses rise and Wall st. questions their ability to navigate the late innings of the economic rise cycle.

“Retail stock weakness and volatility have regrettably been relentless, ” Cowen analyst Oliver Chen said in a research report Friday. The S& P 500 ‘s retail index( XRT) has slid more than 20% over the last three months.