ASOS is having a rough month. Kate Bostock, the UK online retailer’s new Executive Director of Product and Trading, quit somewhat abruptly after spending roughly six months with the company. ASOS had spent over a year courting Bostock, the former head of fashion for Marks & Spencer, as she was viewed as the businesswoman whose retail knowledge and contacts would take online fashion business Asos to the next stage.

And now, the online giant has been slapped with a lawsuit, stemming from its online sales in the U.S. Assos, a Swiss company that sells clothing, particularly cycling clothing and accessories, has filed suit against the similarly-named fashion brand, alleging that it is violating its federally registered Assos trademark (which extends to clothing).

Anton and Roger Maier allege in their trademark infringement suit, which was filed on Monday in a Maryland federal court, that Assos has “generated a substantial reputation of goodwill” and that by offering for sale via the internet clothing, footwear and head gear and other fashion accessories under their mark, ASOS “is creating a likelihood of confusion, including likelihood of association.”

In 2011, Assos prevailed in a similar suit in Switzerland. The company persuaded regulators at the European Union’s Office for Harmonisation in the Internal Market (OHIM) that consumers could become confused due to the similarity between the two brand names, and as a result, the court held that ASOS is prevented from selling products under that name in the cycle clothing company’s home country.

As for whether the court will rule in Assos’ favor, I’m not entirely sure, as Assos is primarily a cycling-clothing company, and not a fast fashion retailer. However, in Assos’ defense, the brand is trying to be fashion-forward, as you may have notice that the model in the ad campaign above is wearing the Cage Booties from YSL’s Spring 2009 collection – along with her cycling gear.