Shares in Gap (GPS - Get Report) tumbled Monday after hours after the retailer reported its same-store sales for April and previewed its first-quarter results.

The company said same-store sales were down 7% for the four weeks ended April 30, while comparable sales were down 5% for all of the first quarter, ended April 30. Gap also said net sales or revenue declined to $1.12 billion from $1.21 billion last April. For the entire first quarter, Gap revealed revenue was $3.44 billion, compared with $3.66 billion for the same period in 2015.

The retailer's shares plummeted $2.79, or 12.8%, to $19.02 on Monday evening.

While same-store sales were down for all three banners of Gap, Banana Republic and Old Navy, Gap saw the smallest decline in the first quarter, 3%, while Banana Republic was down 11% and Old Navy was down 6%.

Because of the poor results, Gap said it is weighing options for both the Banana Republic and Old Navy businesses largely outside of the U.S. to focus on the markets with the most potential.

According to a Monday note from Piper Jaffray senior analyst Neely Tamminga, the firm is embracing a "wait-and-see" approach on whether to reconsider its underweight rating, looking in particular at proof of improvement on sell-through and promotions.

The analyst report specifically focused on the retail group's "higher-than-planned inventory levels, which pressured the gross margin rate," while heading into April.

The firm's lowered its price target for Gap, however, to $21 per share from $25, based on an enterprise value that is 5 times estimated Ebitda for fiscal 2017.

Tamminga also noted Gap's management said it expects earnings per share of 31 cents to 32 cents for the first quarter. That's lower than either the firm's previous expectation of 38 cents per share or the consensus estimate of 44 cents per share.

The new numbers, meanwhile, undermine the theory that Gap's performance was stabilizing, although that progress likely would be negated by the poor performance of Old Navy.

The great hope would be for all of Gap's banners to do well simultaneously, though that has proved elusive.

Still, the retailer probably would be happy at this point if just one of its brands finally showed some positive momentum.