Amazon plans to hold a second shopping event for Prime members, this one in the fourth quarter, according to a notice viewed by CNBC, marking the first time the company will hold two such events in the same year. It comes as Amazon gears up for Prime Day on July 12 and 13, its big annual sale designed to attract new subscribers.

The company recently began notifying select third-party merchants of a "Prime Fall" deal event via its internal seller portal, called Seller Central. The notice doesn't announce any dates, but instructs sellers to submit limited-time "lightning deals" by July 22, well in advance of the fourth-quarter event.

"The Prime Fall deal event is a Prime-exclusive shopping event coming in Q4," the notice states. "Submit recommended Lightning Deals for this event for a chance to have your deal selected!"

The fall event could help drum up additional sales for Amazon, which announced in April that it had booked the slowest quarterly revenue growth since the dot-com bust in 2001. It could also help retailers clear out some of the extra inventory they've accumulated as inflation squeezes shoppers, and they shift their spending to areas like travel and entertainment.

Analysts have voiced concerns that Prime Day has lost some of the momentum it once had, pointing to slowing sales growth, smaller order sizes and more muted promotion on Amazon's website. Jefferies analysts on Monday predicted Prime Day will contribute $8.1 billion in gross merchandise volume this year, which is "consistent with the summer event last year."

Amazon has increasingly looked beyond Prime Day to entice shoppers, launching deals focused on specific categories. Last October, for example, the e-commerce giant held its first beauty products event, and in May it held "Amazon Pet Day."

An Amazon spokesperson declined to comment on the event, which was previously reported by Business Insider.

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