Women's sports merchandise is an estimated $4 billion industry but fans still can't find the items they're looking for

• The women's sports merch industry is worth an estimated $4 billion annually, per a new report.
• But fans have complained about a lack of retailers, minimal options, and low inventory.
• Small companies are stepping up, but questions remain over how bigger brands will meet fans' demand.

As a two-time All-American, two-time World Cup winner, and National Women's Soccer League champion, Ali Krieger has had many unforgettable experiences throughout her career.

One was the first time she saw a fan wearing her jersey.

It was 2007, and Krieger, then 23, was playing for FFC Frankfurt, now known as Eintracht Frankfurt, in the German women's league, Frauen-Bundesliga, when she saw her name emblazoned across a fan's black-and-white jersey.