After more than a decade as a privately held company, Chattanooga, Tennessee-based U.S. Xpress Enterprises has filed the paperwork for an initial public offering.

The truckload carrier has filed with the Securities and Exchange Commission for an IPO of up to $100 million, but the proposed IPO price is an estimate solely for figuring the filing fee. Pricing has not yet been announced.

Founded in 1985 in the wake of deregulation by Max Fuller and Pat Quinn, U.S. Xpress booked $1.6 billion in sales for the 12 months ended March 31, 2018, according to Renaissance Capital. It plans to list on the NYSE under the symbol USX.

The company previously was publicly traded starting in 1994, but was taken private in 2007.

According to the prospectus filed with the SEC, U.S. Xpress is the fifth largest asset-based truckload carrier in the United States by revenue, generating over $1.5 billion in total operating revenue in 2017.

As of March 31, the fleet consisted of approximately 6,800 tractors and approximately 16,000 trailers, including approximately 1,300 tractors provided by independent contractors.

“For much of our history, we focused primarily on scaling our fleet and expanding our service offerings to support sustainable, multi-faceted relationships with customers,” the company pointed out in the filing. “More recently, we have focused on our core service offerings and refined our network to focus on shorter, more profitable lanes with more density, which we believe are more attractive to drivers.”

The company also has been going through a leadership transition over the past three years. Founder Max Fuller became executive chairman, with a role focusing more on long-term strategy and innovation, with son Eric Fuller now president and CEO.

These changes, according the IPO filing, “instilled a new culture of professional management. These changes, which are ongoing, helped us to maintain relatively stable profitability during the weak truckload market of 2016 and early 2017 and drive significant improvements to profitability during the strong truckload market beginning in the second half of 2017. This momentum was reflected in our first quarter of 2018, which produced a 300 basis point improvement in our operating ratio, compared to our first quarter of 2017, and a 330 basis point improvement in our Adjusted Operating Ratio for the same period.”

Related: Inside U.S. Xpress' Award-Winning Leadership Development Programs