Gap Inc.'s shares plummeted on Friday, after the apparel giant reported a decline in holiday season sales across its many brands, including its stalwart brand, Old Navy. The company's stocks sank to its lowest levels in almost four years, sinking more than 14 percent and closing at $22.91, according to The Los Angeles Times.

Overall, the San Francisco clothing giant is having a pretty rough time with its overall shares down nearly 47 percent from last year's levels. With sales going down across the company's numerous brands, net sales for Gap decreased 4 percent to $2 billion in the five-week period that ended on Jan. 2.

Its other brands, such as Banana Republic, experienced a 9 percent decline in sales. Even Old Navy, which showed its resilience with strong holiday sales in 2014, experienced a huge 7 percent decline in sales, reports The Street.

Notably, sales in Gap stores are the ones that are actually quite stable, as sales in the 2015 holiday season only dropped 2 percent in the company's flagship stores.

Gap, together with a number of prominent, traditional apparel companies, has recently struggled to keep pace with newer, fast fashion retailers like Zara, H&M, Uniqlo and Forever 21, according to KRON4 News.

Apart from the challenges from competitors, the company has also lost a prominent leader, with former Old Navy global president Stefan Larsson, who is credited for much of the brand's success, leaving the company to become the CEO of Ralph Lauren.

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