The Quickie brand wheelchair is the most popular customized wheelchair on the market. Its market share is 90 percent. Other manufacturers produce special-use wheelchairs that fold, that are made of mesh and lighter frames, and that are easily transportable. These manufacturers do not compete with Quickie on customized chairs. One manufacturer of the alternative wheelchairs has stated, “Look, it’s an expensive market to be in, that Quickie market. We prefer the alternative chairs without the headaches of customizations.” Another has said, “It is such a drain on cash flow in that market because insurers take so long to pay. We produce chairs that buyers purchase with their own money, not through insurers. Our sales are just like any other product.” Quickie entered the market nearly 40 years ago and is known for its quality and attention to detail. Buying a Quickie custom chair, however, takes time, and the revenue stream from sales is slow but steady because of the time required to produce custom wheelchairs. Has Quickie violated the federal antitrust laws with its 90 percent market share? Discuss.