Launched in June, Google Checkout allows users to make purchases from Internet retailers without having to repeatedly enter credit card details. Since October, the firm has been offering strong incentives for merchants to join up, including free processing of credit card transactions.

Management claims that Checkout handled $900m of transactions during the quarter, a figure analysts estimate would represent about 12% of the domestic online non-credit card payment market.

At a conference call to announce the results, Google co-founder Sergey Brin was quizzed on whether the additional spend required to convert merchants had paid off in material returns. "I don’t have any data," he said. "But we’ve seen a substantial increase in the likeliness of people clicking on an ad with a Google Checkout badge."

Brin went on to say that plans are afoot to expand the availability of Checkout beyond the US and to deepen integration with other products.