The shares fell 10 percent to $25.60 at the close in New York for the biggest decline since August 2009.

Lowe’s trimmed the number of sales discounts by 30 percent in the first quarter as Chief Executive Officer Robert Niblock shifts to consistent everyday prices to compete with faster- growing Home Depot Inc. Sales by stores open at least a year increased 2.6 percent in the quarter, trailing the gain of 4.2 percent projected by analysts.

“Lowe’s is still in the earlier stages of executing its turnaround,” Christopher Horvers, an analyst at JPMorgan Chase & Co. in New York, said today in a note. He rates Lowe’s as neutral, equivalent to a hold rating, and said its results signal “sales trends decelerating, jobs softening and the summer being a seasonally weak period to own retailers.”

Profit will be as much as $1.83 a share in the year ending Feb. 1, down from a previous projection of a maximum of $1.85 a share, the Mooresville, North Carolina-based retailer said today in a statement. That trailed the average estimate of $1.87 by analysts in a Bloomberg survey.

A reduction of promotions hurt appliance sales last quarter. Purchases exceeding $500 declined 1 percent and increased 2 percent for purchases of $50 and below, Chief Financial Officer Robert Hull said on a conference call today.

Lowe’s net income rose 14 percent to $527 million in the quarter ended May 4 from $461 million a year earlier. Excluding some items, per-share earnings advanced to 44 cents, compared with the average estimate of 42 cents.

Home Depot, based in Atlanta, last week reported same-store sales increased 5.8 percent.