Reported by BBC Technology
Chief executive John Ternus was presenting his first Apple results since taking over from Tim Cook
Apple has said it does not know when it will get more of its new foldable iPhones back in stock as the company heads towards the key Christmas trading period.
The iPhone Duo sold out just over a week after its launch, despite being Apple's most expensive smartphone at a cost of nearly $2,000.
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The company warned of "constraints" in sourcing key components and admitted it was "really hard to predict when supply and demand will be in balance".
Meanwhile, Apple's new chief executive John Ternus said the firm was seeing an "unprecedented" price rise in memory costs, including chips, as the artificial intelligence (AI) industry continues to invest billions of dollars in building data centres.
Ternus launched the Duo after he took over from previous boss Tim Cook in September.
It is the smartphone's first major design change in almost 20 years but some buyers have reported problems with the Duo's screen .
Last week, the company said it would replace any handsets that were affected by an issue that caused a "small number" to crack along the inside fold.
As it released its latest financial figures on Monday, Apple's executives did not mention any problems with the iPhone Duo.
Ternus said he was "thrilled" by the early reaction to the foldable phone. Chief operating officer Sabih Khan said the company was working hard to get the Duo "into the hands of our customers as quickly as possible".
Apple's results for the three months to 26 September did not include sales of the Duo, which was released at the end of October.
Nevertheless, Apple said it had sold more iPhones globally over the last year than ever before.
Sales of Mac computers also grew over the three months by 27% to a record $10.7bn.
Overall, Apple's sales between July and September rose from $102bn to $114bn. Pre-tax profit also increased, from $32.8bn to $36.1bn.
However, sales for both the iPad and Apple's wearable products, including its headphones and watch, fell by 10% and…