401k contribution-pro rata required if start program at end of year?

[Guest donmartin]

For a 401k contribution, is a pro rata contibution required if open up a new plan at end of year? On Dec., 2004 client opened a 401k plan using the protype at a major stock brokerage company. He then made a contribution thru employee salary deferal (no employer contribution). Now employer is filling out form 5500 and the question has been raised by the CPA, must a contribution for the max. employee deferral of $ 13,000 in 2004 have been made evenly throught the year (once a month), or can it be done towards the end of the year in one lump sum? Client was unable to contribute evenly each month because the 401k program was not opened up by employer until 12-2004. This is the new 401k "uni-k" for one person "S" corps, which is why the brokerage company did not make the protype available until Dec., 2004.