Amazon expanded its annual Prime Day sales event this year to four days from two. But now that the event is up and running — it started Tuesday and runs through Friday — there may be signs it’s losing some of its bargain-hunting appeal among consumers.

Amazon Prime Day is coming to an end, so you'll have to be quick to get the last of the best Prime Day drone deals, which are still available.

Momentum Commerce, which manages online sales for 50 brands, said its Amazon purchases plunged 41% on Tuesday when compared with the start of Prime Day last year.