The company, which provides credit card fraud prevention systems to large institutions such as Amex, NatWest and Barclays, said the board is satisfied that the amount of the payment involving Brian Raven, the chief executive, and Oliver Cooke, the finance director, was "not material". The payment was "neither intended to confer, nor conferred, any personal gain on either Raven or Cooke", the company said. However, the resulting loss of confidence in the two directors made their positions untenable, it stated.
"Neither Raven nor Cooke is seeking or will receive any compensation in connection with their resignations other than the retention by them of certain share options," Card Clear added.
The company has not informed any of its regulators of the affair because of the small size of the payment concerned, a spokesman said.
It is also highly unlikely that the company will take any legal action against the departing pair.
The company, based in Woking, Surrey, said that Nigel Whittaker, the non-executive chairman, will take over as caretaker executive chairman while it seeks replacements.
From 1983 to 1995 Mr Whittaker was director of corporate affairs at Kingfisher, the retail group. He will be supported on the Card Clear board by Barrie Brinkman, the managing director of the recently acquired information technology company HTEC, and Steve Callaghan, the managing director of Card Clear UK.
The company also said its auditors, Coopers & Lybrand, will help in finding suitable financial management.
Under the departure terms agreed with the board over the weekend, Mr Cooke will retain one million of the 2.6 million share options granted to him under the company's executive share option scheme. Mr Raven has 958,000 founders' options over shares in the company, exercisable at 12.5 pence per share.