Is it possible for someone to raise bids on his own item?

[superlulu514]

I suspect someone to raise bud on his own items with private listing - bidders' identities protected.

How do I find out? 

[oskye]

It is possible - but definitely NOT allowed.  It is called "Shill bidding" and a grave violation of policy.

http://pages.ebay.com/help/policies/seller-shill-bidding.html

Report it, but you need reasonable grounds.

[femmefan1946]

If the other bidder is actually winning, the seller is not shilling, you are just being outbid.

If the other bidder is cancelling his bids and not rebidding, he could be trying to find your maximum bid and pushing you to it.

The simplest way to counteract both is to bid once, bid late and bid your maximum.

In this case” bid late” would be in the last few minutes, even seconds, of the listing. If the timing is awkward, you can use an electronic “sniping” service like eSnipe.