VF Corp. , owner of Lee and Wrangler jeans, is exploring strategic options for its denim business that could include a sale or spin off of the classic American brands, according to people familiar with the situation.

The apparel conglomerate has owned Wrangler and Lee for decades and they were once its core, but the company’s jeans sales have slowed in recent years as more women opt for yoga pants or premium denim brands like J Brand or Frame.

VF, which has a market valuation of $38 billion, has been paring back its wide-ranging portfolio to focus on its fastest-growing brands, such as Vans sneakers, The North Face jackets, and Timberland boots.

VF’s denim business last year had $2.66 billion in sales and $422 million in profit. A typical multiple in the apparel industry could value the business at several billion dollars. It isn’t clear what other brands might be part of the company’s review.

The overall U.S. jeans category had total sales of $16.2 billion in 2017, down from $18.8 billion in 2013, according to Euromonitor International. One big brand bucking the downward trend is Levi Strauss & Co., whose revenue increased 8% in its most recent fiscal year.