Sept 20 (Reuters) - Xplor Technologies Llc, a payments company backed by private equity firm Advent International, confidentially filed paperwork for an initial public offering in the United States on Monday. The Atlanta-based company was formed after Advent merged here two of its portfolio payments companies Transaction Services Group (TSG) and Clearent, which together processed over $27 billion in payments in 2020, to form Xplor earlier this year. Xplor could fetch a valuation of $4 billion to $6 billion, Bloomberg News reported here in August, citing people familiar with the matter. The company, which runs a cloud-based payments processing platform, also makes enterprise software solutions that are used across five industrial verticals including education, health and fitness, boutique wellness, field services and personal services.