• Some skepticism on adding outlets as fewer shoppers show up
  • The expansion means about $160 million in capital spending

Something’s not adding up for PetSmart Inc. lenders.

The company is already loaded with debt from a pricey e-commerce acquisition in 2017, and earnings have plunged as the $3 billion takeover of Chewy.com proves tough to integrate. Yet PetSmart’s managers plan to open as many as 60 new stores in 2018–after adding more than 100 over the past two years–according to people who listened to an earnings call late Thursday.

Some holders of the retailer’s $8 billion in bonds and loans questioned the brick-and-mortar expansion during the conference call, given pervasive weakness in retailing and PetSmart’s apparent goal of moving more business online, the people said. They asked for anonymity because the call for the closely held company was open only to investors and other invited market participants. The doubts are reflected in PetSmart’s debt, with some of its bonds selling for less than 60 cents on the dollar.

PetSmart executives on the conference call acknowledged the decline in…