HOFFMAN ESTATES, Ill. — Sears Holdings Corp. extended its string of unprofitable quarters to nine, posting a wider second quarter loss as sales declined at many of its businesses, including Kmart, Sears Auto Center and Sears Canada.

Sears Holdings Corp. extended its string of unprofitable quarters to nine, posting a wider second quarter loss as sales declined at many of its businesses, including Kmart, Sears Auto Center and Sears Canada.

The company said its net loss for the three months through August 2 expanded to $573 million, or $5.39 a share, from $194 million, or $1.83, a year earlier. Sales declined 9.7% in the period, the company’s 30th consecutive quarter of declining sales.

Sears’ year-earlier results included Lands’ End, the clothing retailer that the company spun off in April.

Company executives said they might shutter more than the 130 stores they were planning to close this year.

The company, parent of Sears department stores and the Kmart discount chain, is controlled by hedge fund billionaire Edward Lampert, who characterized the second quarter financial results as "unacceptable."

Lampert is trying to reverse the retailer’s slide by beefing up digital operations and the retailer’s Shop Your Way rewards programs. Loyalty program members generated 73% of eligible sales in the quarter, the company said.

Lampert, Sears’ largest shareholder, took over as chief executive officer in February 2013 and has been under pressure to turn around the business. He has sold assets and sought to shrink the company’s store base as he seeks to halt a string of operating losses.

The company said it continues to explore a sale of its 51% stake in Sears Canada or the sale of the entire Canadian company.

Sales in the three months dropped to $8.01 billion from $8.87 billion. Sales at stores open at least a year rose 0.1% at Sears and fell 1.7% at Kmart. Online sales rose 18% in the period.

Sears last month named former Tesco PLC executive Alasdair James to head the Kmart ­business.