A US financial regulator has opened an investigation into claims Apple’s credit card offered different credit limits for men and women.
It follows complaints – including from Apple’s co-founder Steve Wozniak – that algorithms used to set limits might be inherently biased against women.
New York’s Department of Financial Services (DFS) has contacted Goldman Sachs, which runs the Apple Card.
Any discrimination, intentional or not, “violates New York law”, the DFS said.
The Bloomberg news agency reported on Saturday that tech entrepreneur David Heinemeier Hansson had complained that the Apple Card gave him 20 times the credit limit that his wife got.
In a tweet, Mr Hansson said the disparity was despite his wife having a better credit score.
Later, Mr Wozniak, who founded Apple with Steve Jobs, tweeted that the same thing happened to him and his wife despite their having no separate bank accounts or separate assets.
Banks and other lenders are increasingly using machine-learning technology to cut costs and boost loan applications.
But Mr Hansson, creator of the programming tool Ruby on Rails, said it highlights how algorithms, not just people, can discriminate.
US healthcare giant UnitedHealth Group is being investigated over claims an algorithm favoured white patients over black patients.
Mr Hansson said in a tweet: “Apple Card is a sexist program. It does not matter what the intent of individual Apple reps are, it matters what THE ALGORITHM they’ve placed their complete faith in does. And what it does is discriminate.”
He said that as soon as he raised the issue his wife’s credit limit was increased.
The DFS said in a statement that it “will be conducting an investigation to determine whether New York law was violated and ensure all consumers are treated equally regardless of sex”.
“Any algorithm that intentionally or not results in discriminatory treatment of women or any other protected class violates New York law.”
The BBC has contacted Goldman Sachs for comment.
On Saturday, the investment bank told Bloomberg: “Our credit decisions are based on a customer’s creditworthiness and not on factors like gender, race, age, sexual orientation or any other basis prohibited by law.”
The Apple Card, launched in August, is Goldman’s first credit card. The Wall Street investment bank has been offering more products to consumers, including personal loans and savings accounts through its Marcus online bank.
The iPhone maker markets Apple Card on its website as a “new kind of credit card, created by Apple, not a bank”.