NEW YORK — J.C. Penney Co. was the biggest loser Thursday. Its shares plunged nearly 17 percent to $17.57, the largest decline on the Standard & Poor’s 500 index, a day after the department-store chain posted its fourth consecutive quarterly loss — one that was larger than expected.
The shares have lost about 60 percent since January 2012, when chief executive Ron Johnson unveiled a plan to ditch hundreds of sales in favor of everyday low prices. Thursday’s fall is the latest sign Johnson’s strategy may fail. ‘‘I fear it will be much worse, as consumers continue to walk away from J.C. Penney and its financial health continues to deteriorate,’’ said Walter Loeb, an independent consultant in New York.
Johnson on Wednesday acknowledged the 1,100-store chain had made some mistakes. He also said Penney would start offering sales every week.
Penney’s quarterly loss widened to $552 million, or $2.51 per share. Revenue fell 24.8 percent to $12.98 billion. Revenue at stores open a least a year — a crucial gauge — dropped 31.7 percent.
For the fiscal year, Penney lost $985 million, or $4.49 per share, compared with a loss of $152 million, or 70 cents, in the year ended Jan. 28, 2012. Revenue fell 24.8 percent to $12.98 billion.