Apple CEO Tim Cook addresses the crowd during the Apple Worldwide Developers Conference (WWDC) 2013 in San Francisco, California June 10, 2013 / Reuters

'Obviously I can’t predict the future, but our performance so far this quarter is reassuring,' Cook said in the rare message

Tim Cook has issued a very rare statement on Apple’s recent weak share performance, assuring investors that the company’s performance was unlikely to be hit by the financial chaos that is engulfing the world’s markets.

Tim Cook, the company’s CEO, broke his usual silence on the company’s performance to say that it had still been seeing strong results in China, and that he remained optimistic about the company’s outlook there.

The intervention seemed to pull the company's stock price up massively in the hours after it was made. The company's shares were trading up towards the end of the day — despite the lingering concerns about China — in line with many other US shares.

Apple has been public about its strategy to expand in China, and so has received extra attention as worries about the country’s economy have dragged down share prices across the world. Its stock was trading down more than 5 per cent on Monday, the latest fall in a run of weak performance.

Cook said that he was breaking his usual silence because the “question is on the minds of many investors”.

“I can tell you that we have continued to experience strong growth for our business in China through July and August,” Cook wrote in an email to Jim Cramer, the US business TV personality, that was posted online during the stock slide and confirmed by CNBC.

“Growth in iPhone activations has actually accelerated over the past few weeks, and we have had the best performance of the year for the App Store in China during the last two weeks.

“Obviously I can’t predict the future, but our performance so far this quarter is reassuring. Additionally, I continue to believe that China represents an unprecedented opportunity over the long term as LTE penetration is very low and most importantly the growth of the middle class over the next several years will be huge.”

Apple has been working hard to push into China, which has become its second biggest market after America. But that has also meant that the company has borne a large part of the brunt of worries about the country’s economic outlook, and its stock has often traded down as Chinese shares have done so.

Moves in the country have included new environmental initiatives and product launches made in part to suit Chinese tastes — as well as Tim Cook’s joining Weibo, the country’s equivalent of Twitter.