Mighty Jeff Bezos has hit a wall.

The number of US shoppers who are willing to fork out $99 a year for Amazon Prime had zero growth in the third quarter, according to a report on Thursday.

The report, from Morgan Stanley, showed that 40 percent of individuals questioned in a survey said they were Prime members — exactly the same percentage response as in a fourth quarter 2016 survey.

The latest survey marked the first time that consecutive surveys revealed zero growth.

It’s the first sign that Amazon, which continues to grab more holiday spending this year than last, might be “plateauing” in its oldest market, wrote Morgan Stanley analyst Brian Nowak.

In the first quarter of 2016, 35 percent of 1,000 people questioned said they were Prime members.

One quarter earlier, that total was at 26 percent.

“Exponential growth doesn’t happen forever,” said Sarah Engel, chief marketing officer of DynamicAction, a retailing analytics company. But this report was “a bit surprising,” Engel added, “because every report about Amazon shows growth on top of growth.”

The Seattle-based behemoth will need to do a better job of courting the AARP crowd and low-income consumers if it hopes to move the needle on Prime, Nowak claims.

About 40 percent of people ages 55 and older do not use Prime, according to the survey.

Efforts by Amazon, led by Chief Executive Jeff Bezos, to push into health care and pharmacy services is one way Amazon is trying to reach older consumers, industry experts said.

This summer it began offering a $5.99-a-month version of Prime to people receiving government assistance.

Amazon said the 27 percent discount offer for low-income consumers was just the first of what will be several ways for customers participating in government assistance to qualify for Prime.

Most experts believe low-income consumers will be a tough sell. But not everyone is convinced that Amazon is stumped.

“I don’t think this is a sign of Amazon slowing down,” said Nii Ahene, chief operating officer of CPC Strategy. “They’ve reached 50 percent of households, and that’s a natural benchmark. It’s going to be an uphill battle” for them and would be for anyone who reached that threshold, Ahene said.

Amazon’s investors unfazed by the report. Its shares closed up .09 percent, to $1,174, on Thursday.