Shoes.com is taking stock in socks. The online footwear and apparel retailer announced Thursday the acquisition of California-based sock brand Richer Poorer for an undisclosed amount.

Richer Poorer was launched by Iva Pawling and Tim Morse in 2010 as a men’s sock label with a mission to offer products with a unique and balanced approach to design and branding. The company has maintained a 100 percent growth rate year over year, expanding into women’s and children’s socks, as well as new product categories like underwear. It will soon launch basic tees.

Pawling said the sale will help accelerate the company’s growth while “remaining true to its brand ethos.” The company will continue to build its operations in San Juan Capistrano, California.

Shoes.com is in an investment phase. In early 2015, the e-tailer purchased a minority stake in men’s footwear startup, Boston Boot Company.

In a release, Shoes.com CEO and Co-Founder Roger Hardy, said, “Not only is this acquisition a natural extension of our business but it demonstrates our commitment to expanding our offering into the accessories and apparel categories. Socks have transformed from commodity to fashion statement – this is reflected in the growth of the category and represents an exciting opportunity for us to diversify our product assortment beyond footwear.”

Since 2010, the men’s sock business has grown by double-digits each year. In 2014, the men’s sock category in the U.S. increased 14 percent. The hosiery market is expected to reach $25.9 billion by 2018.