CSG International (CSGI) is a multinational corporation headquartered in Englewood, Colorado. It provides Business Support Systems (BSS) software and services, primarily to the telecommunications industry.

CSG was founded by Neal Hansen as a division of First Data in 1982. It became an independent corporation when it was acquired by CSG Holdings in 1994 for $137 million. A contract with Tele-Communications Inc. (TCI), the largest cable TV business at the time, was influential in the company's growth from $80 million in revenue in 1994 to $171 million by 1997. CSG went public in 1996. A dispute with TCI over pricing led to a $120 million arbitration settlement in 2002 with Comcast, who acquired the TCI business. The two continued to do business together and expanded their relationship in 2014. CSG made more than ten acquisitions in the 2000s, mostly of companies that sold billing, customer service and operations software.

CSG International was founded in 1982 by Neal Hansen under the name Cable Services Group (CSG) as a division of the payment processing company First Data Corporation. At the time First Data was operated by American Express, which acquired a controlling interest in the company in 1980. CSG became a part of the American Express Information Services Company, which was formed in 1989. The CSG group's first large-scale billing statement processing center, which prints and mails bills to consumers, was established in Omaha in 1990.

Hansen left the Cable Services Group one year after it was founded to become CEO of Applied Communications, where he met George Haddix. Hansen and Haddix formed CSG Holdings with Morgan Stanley and Trident Investment Group in 1994, which acquired Cable Services Group that year for $137 million. In November 1994, Cable Services Group was renamed to CSG Systems International.

CSG was the second largest billing services provider for the US cable television industry by 1994, serving 27 percent of cable TV subscribers. However, according to The International Directory of Company Histories, its profit margins were small and the company was "still in need of a turnaround." Broadcasting & Cable said CSG had lost direction and become complacent. Haddix and Hansen implemented changes at the company, which prompted 350 out of 500 employees to leave the firm within a few months.

The new CSG International grew quickly. The convergence of phone, internet, on-demand movies, and other services created more complex billing arrangements between telecommunications companies and consumers, which led to more extensive use of billing services providers like CSG. Professional services and international clients, which were previously not a significant portion of revenues, grew to 22 percent of revenues by the mid-1990s.

In order to pay off debt and raise funding for acquisitions, CSG held an initial public offering in February 1996, which valued the firm at five-fold its original acquisition price. CSG grew from $80 million in annual revenues when it was acquired, to $132.3 million when it went public in 1996 and $171.7 million by 1997.

In the 1990s, Tele-Communications Inc. (TCI) and Time Warner scrapped efforts to create internal billing software and hired CSG International. The 15-year agreement CSG signed with TCI on August 11, 1997 made CSG the largest vendor in the industry and was the primary contributor to its growth in the '90s. By 2001, the deal was responsible for 45 percent of CSG's revenue. As part of the deal, CSG also acquired TCI's internally developed software, SummiTrack, for $106 million. CSG's services to TCI included billing, customer management and payment processing for TCI customers. In October 1997, CSG International signed its first deal with a utilities company, mc2.

At the end of 1997, CSG co-founder George Haddix retired, and former EVP Jack Pogge was appointed President and Chief Operating Officer in his place. In 1999 CSG began constructing a new bill processing center in Florida in a deal with local government, which expanded roads and provided other incentives. In 2002, CSG acquired the billing software interests of Lucent Technologies for $260 million. The deal was estimated to increase CSG's revenues by 38 percent and its headcount by 65 percent. 200 Lucent employees were laid off as a result of the acquisition. An additional 100 - 150 CSG employees were laid off later that year in response to poor economic conditions.

AT&T acquired TCI in 2000, inheriting its agreement with CSG. AT&T alleged CSG was not abiding by the contract's terms to provide favorable rates. A legal dispute between the two companies began in 2001 in arbitration court. Before the dispute was resolved, AT&T Broadband was acquired by Comcast, who wanted to use its own billing and customer service vendor. In October 2002, a judge ruled that CSG owed Comcast a $120 million refund and that it had to reduce its prices. The two companies disagreed over whether the ruling would allow Comcast to halt their agreement before the end of its term. CSG and Comcast reached new agreements or extensions in March 2004 and in 2008. In 2014 its work with Comcast was expanded to cover all of its customer support and billing for residential services.

In March 2005, co-founder Neal Hansen retired at the age of 64. Ed Nafus, prior president of the broadband services division, took his place. Nafus was replaced as CEO by Peter Kalan, at the end of 2007. In November 2015, it was announced that Bret Griess would be succeeding Kalan as president and CEO.

As of 2016, CSG International now has 33 offices in 22 countries across the world. This does not include minor 'satellite offices'.

CSG International provides software and services for managing customer data, analyzing that data, billing and customer service. For example, customer service representatives may use CSG systems to look up a consumer's records and add a new service, or business analysts may mine customer data for trends. According to the company's website, its primary product areas are revenue management, content management and monetization, and customer interaction management. CSG also prints and mails billing statements to consumers and provides call-center services.

CSG International originally sold two versions of its billing process outsourcing services. Under new leadership in 1994, it began developing additional software and providing consulting to in-house billing departments. During this period it developed CSG Workforce Express, a suite of software products that manage the dispatch of technicians and other logistics at customer sites. Workforce Express consists of three applications: CSG Workforce Management, CSG TechNet and CSG TechNet CE, which integrate with CSG's databases and billing systems. It also developed CSG Care Express, which is for creating online self-service portals for consumers to view and pay their bills online.

In the 1990s CSG introduced the ACSR (Advanced Customer Service Representative) system. An extension to ACSR called ProfitNow! was introduced in 2003. ProfitNow! used a consumer's account data to advise customer service representatives on the likelihood of a caller cancelling their service or buying a new product. It was later turned into an online system with a user interface similar to Microsoft Windows at CSG.net. CSG purchased the Kenan FX software from Lucent Technologies in 2002. Kenan software managed billing and ordering and provided middle-ware to help various customer service and billing products integrate with each other. CSG NextGen was introduced for international markets, with support for multiple languages. In March 2014, CSG added a cybersecurity suite to its product portfolio, under the name CSG Invotas. The company released CSG Ascendon, a digital platform for communications service providers, in March 2015. The platform uses content monetization and delivery systems without making excessive changes to existing infrastructure. In November 2015 the Invotas unit was spun off into a separate entity. Invotas was acquired by FireEye in a transaction that closed February 1, 2016.

CSG International has three subsidiaries: CSG Systems, CSG Systems Software and CSG Services. Its subsidiaries offer products and services, while the parent company, CSG Systems International Inc. is listed on the NASDAQ stock exchange. As of 2015, its largest clients were Comcast, DISH and Time Warner Cable, representing 24, 14 and 12 percent of its revenues respectively. CSG spends approximately 14 percent of its revenues on research and development. Its revenues are about 77 percent from payment processing and related services, 12 percent from software and the remainder for ongoing technical support. 85 percent of revenues are from the Americas.