American Express Co has assured Industrial and Commercial Bank of China Ltd (ICBC) it wants to keep its stake in the lender after entering into a contract to hedge fluctuations in the stock price, a source with direct knowledge of the matter told Reuters on Wednesday.

Shares in ICBC, the world's biggest bank by market value, has fallen 5.7 percent in the past two days after Goldman Sachs executed a $479 million block deal. Hong Kong's benchmark Hang Seng index is down nearly 3 percent in the same period.

There has been some speculation that American Express was paring its exposure to ICBC, but two sources close to the deal said American Express was only locking in the value of its ICBC holdings through a hedging contract structured by Goldman.

The sources were not authorized to speak to the media. American Express did not immediately respond to a request for comment, while ICBC was not available for an immediate comment.

One of the sources said American Express's stake in ICBC and its role as a strategic investor was unchanged, adding that the hedging deal was struck with Goldman to reduce the impact on earnings from any volatility in ICBC's share price.

American Express holds 638 million shares in ICBC, valued at about $463 million based on its closing price of HK$5.64 on Wednesday.