I think the best thing to do is to actually ask the agent (or ask your agent to ask the listing agent) why he is holding the offers? Is there a current offer they are already processing on the property? Has the bank giving him something in writing that says they don't want the offers submitted until a specific date? There could be lots of reasons, but I think the best way to get an answer is to ask him directly.
Like Keith stated sometimes the Seller (Bank or Person) may request that for the first few days all offers be gathered and then submitted and reviewed at one time. I also agree with Keith that if you are represented your agent should be able to find out the status.
Here is the California Association of Reators, rule releated to Presentation of Offers:
9.5 Submission of Offers and Counter-Offers. The listing broker shall submit to the seller/landlord all offers until closing unless precluded by law, governmental rule or expressly instructed by the seller/landlord otherwise. The cooperating broker acting for buyer/tenant, shall submit to buyer/tenant all offers and counter-offers until acceptance.
So all offers and counter offers must be presented until the close of escrow.
Do you have a Realtor representing your interests?
Or did you make the offer through the listing agent (L/A)?
Normally the L/A has a fiduciary duty to present all offers. However, in some cases (REOS) the lender will want to give the property some time to "season" on the market. Meaning that the lender (owner) may have asked that the L/A "collect" the offers so they can be considered at one time.
This makes comparing the offers easier. In some cases being first is not being "best". That is why working with a buyer's agent may "help " you. It is not uncommon to have listings, properly priced and marketed, to be in a "multiple offer" situation, and in that case you need a seasoned Realtor to help you"wine the listing" if that is what you want.
If you are represented by a REaltor OTHER than the L/A,. then they should be able to find out what is going on.