To help protect members' privacy, bidder User IDs are hidden on the Bid History and View Item pages for all auction-style listings.

On eBay.co.uk, each bidder is assigned an anonymous name such as 'Bidder 1', 'Bidder 2', which is used consistently throughout the duration of the listing. The colour of the star next to the anonymous ID indicates the bidder's Feedback score (e.g. 10-49 = yellow star). Note that anonymous names may be used for different bidders across different auctions.

On eBay.ie, the anonymous names will use two random characters from the User ID, with three asterisks in between, e.g. 'x***y'. The bidder's actual Feedback score will be shown, and the masked ID is consistent for that bidder across all auctions.

Sellers still see all bidders' IDs on their listings, and each bidder can see their own ID when they're signed in. The winning bidder’s ID is visible to everyone after the auction ends.

Why is eBay making this change?

We’ve found that a high percentage of eBay buyers and sellers have nearly identical email addresses to their eBay User ID (e.g. jsmith123 / jsmith123@email.com). This makes it very easy for online fraudsters to guess members' email addresses and pose as genuine sellers, convincing people to enter into a fraudulent transactions outside of eBay - most commonly via fake 'Second Chance Offers'.

If your User ID makes it easy to guess your email address, we encourage you to change your User ID in My eBay.

We began masking bidders' IDs in early 2007 on auction-style listings once the bid price went over £100. We found it’s been very effective at reducing fraud from fake Second Chance Offers, without affecting bidding activity, so we decided to expand this protection to all auction-style listings.

Doesn't this make shill bidding easier?

eBay takes shill bidding (the use of a secondary bidding account to increase the level of bidding and the apparent value of an item) very seriously. Shill bidding is a breach of policy and we will investigate any reports we receive and take appropriate action against offenders. eBay invests heavily in shill detection systems that enable us to proactively detect and investigate possible shill bidding scenarios with a high rate of accuracy. Our systems collect more information on selling and bidding activity than members can access, to help us detect patterns and accurately identify members who are breaching the policy.

Although the bidder IDs are anonymous, detailed statistics are available for each bidder to help members feel confident in placing a bid. Click on the masked bidder ID on the Bid History page to see details including bid retractions, bidding activity with this seller in the past 30 days (percentage), and bids placed in the last 30 days by category/seller.

How does this affect the Advanced Search by Bidder?

You can't search for another member by their masked User ID. You can search using their full User ID, but you will only see the items that the other member has won.

If you search for your own User ID, you will see all listings that you've bid on in the past 30 days.

Sellers can search for their bidders and see full results (i.e. all listings that the member bid on in the past 30 days) for 48 hours from the time the bid was placed. Similarly, if a potential buyer sends a seller an enquiry via 'Ask a Question' or submits a 'Best Offer', the seller can see all results for 48 hours from the time the enquiry or offer was sent.