Swift Transportation is a Phoenix, Arizona-based American truckload motor shipping carrier. With over 16,000 trucks, it is one of the largest common carriers in the United States. In 2017, Swift announced that it was merging with Knight Transportation, also of Phoenix, to be called Knight-Swift. The merger became effective September 8, 2017.

Carl Moyes was a truck driver hauling produce for C. R. England Trucking in the 1940s out of northern Utah. In the late 1950s Betty and Carl Moyes started a small trucking company in Plain City, Utah, B & C Truck Leasing, and after their son, Jerry, graduated from Weber State University in 1966, they moved the small company to Phoenix, Arizona. Carl, and his two sons, Ronald and Jerry (vice-president), formed the company, as Common Market, in Arizona, that would become Swift.

Operations began in 1966 transporting imported steel from the ports of Los Angeles, California to Phoenix, Arizona, and then returning with cotton from Arizona to be delivered to Southern California.

The name Swift Transportation was purchased from a descendant of the Swift Meat Packing family, when the Moyes family bought the trucking assets of Swift & Company. The three Moyes's and a fourth partner, Randy Knight, grew the business to $25 million in annual revenues by 1984. Jerry became president, chairman, and CEO that same year, and when Carl died in 1985, Jerry bought out his other two partners, his brother Ronald and Randy Knight. Ronald would continue to hold shares in Swift while Randy would become a co-founder in Knight Transportation.

In April 1988 Swift purchased Greenville, South Carolina-based Cooper Motor Lines from Philadelphia, Pennsylvania-based ARA Services.

By 1990, Swift Transportation had grown to a $125 million carrier with over 800 trucks. The company did an initial public offering (IPO) in 1990 and became a publicly traded entity on the NASDAQ market system under the symbol SWFT.

In 1991, with money raised in the IPO, Swift bought Stephens City, Virginia-based Arthur H. Fulton Inc. for $9 million. Fulton was in Chapter 11 bankruptcy protection at the time.

In a similar move, in 2001 Moyes purchased all of the properties, assets, and accounts of Dick Simon Trucking, which had filed for Chapter 11 bankruptcy. Those assets were rolled into Moyes' small Central Freight Lines out of Texas, and later spun off as the separate corporate entity Central Refrigerated Service, which remained wholly owned by Moyes until its subsequent sale to and merger with Swift. The sale was announced in summer 2013, and the merger completed and operating authority officially transferred to Swift On February 1, 2014. Moyes received $180 million in cash for the sale.

The company growth has continued since 1988 with the purchasing of (11) different motor carriers throughout the United States, including M.S. Carriers, of Memphis, Tennessee in 2000. The shareholders of M.S. Carriers obtained a 22% stake in the combined company.

Moyes was about to retire, but was forced out as chief executive officer (CEO) at Swift in October 2005 after a United States Securities and Exchange Commission (SEC) investigation into insider trading. Without admitting or denying wrongdoing he paid a $1.26 million settlement. The Moyes family still controlled about 39% of the issued public stock.

In November 2006 Moyes offered to buy Swift for $29 a share. The offer was raised to $2.4 billion ($31.55 per share) for all outstanding shares not controlled by the family and assuming $332 million in outstanding debt, the transaction was closed on May 10, 2007. To finance the acquisition, Moyes formed Saint Acquisition Corporation, and issued $2.1 billion of a senior secured credit facility and $835 million in second-lien senior secured notes. The company's drivers and eighty-three percent of all outstanding shares (approximately half of those controlled by the family) supported the buyout.

Swift’s terminal network grew to over forty full service facilities in both the continental United States and Mexico, but then closed a few after the 2008 financial recession. The total number of employees dropped from 21,900, to approximately 17,700. Swift owns 100% of Trans-Mex, a Nuevo Laredo, Mexico-based carrier. Swift offers border crossing services at all major Mexican border crossings. Swift maintains a presence in every Canadian Province.

The company operated 16,200 units (12,300 tractors by company drivers and 3,900 owner-operator tractors), a fleet of 48,600 trailers, and 4,500 intermodal containers from 35 terminals in the United States and Mexico, generating just over $2.5 billion in revenue for the year ended December 31, 2009.

Swift Transportation went public once again on December 16, 2010, trading on the New York Stock Exchange (NYSE). The company offered 73,300,000 shares at $11.00 per share, raising almost $766 million, with the proceeds being used for debt reduction. The offering represented 54.9% of the company, valuing the company at $1.86 billion. Due to the economic downturn, the IPO was below Moyes leveraged-buyout (LBO) price of $17.61. With the offering the name officially change from Swift Holdings Corp. to Swift Transportation Company.

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