A huge payment company is heading for a £6 billion London IPO

Management at Worldpay have decided to list the payment processing giant on London Stock Exchange rather than selling the business, after months of um-ing and ah-ing.

Worldpay processes payments for online retailers and also does point of sale processing for transactions in shops. 42% of all checkout sales in the UK using cards are processed by Worldpay.

The company was spun out of Royal Bank of Scotland in 2009 as part of European Union conditions on the bank's state bailout and bought by private equity groups Bain Capital and Advent International.

Sky News first reported that Worldpay was looking to float in London back in June, in what would be one of the biggest listings this year.

But that attracted the attention of potential acquirers. The most recent approach was a £6.6 billion ($10.2 billion) offer from France's Ingenico.

Worldpay on Friday officially said it plans to float the company in London, snubbing the takeover offer.

In a statement CEO Philip Jansen says: "The IPO is an exciting and logical next step as we seek to continue this momentum. It will enable us to access new capital for growth, augment our global proposition and further enhance our ability to serve customers across the world."

Worldpay is a big business, with revenue last year of £863.4 million ($1.34 billion) and earnings of £374.7 million ($583.9 million). The initial public offering of stock will likely value the company around £6 billion.

Here's Worldpay in its own words talking about its scale:

On a typical day, it processes approximately 31 million mobile, online and in-store transactions worldwide, offering access to 326 payment methods in 126 transaction currencies across 146 countries, while supporting approximately 400,000 merchants, including large enterprises and domestic corporates and approximately 377,000 small and medium sized businesses.