The client recognizes the service with a predecessor employer. An employee worked 10 years for the predecessor employer, then left for 7 years and is now hired by the new company. Is he a participant on the date of hire or does he need to meet eligibility requirements?

When we asked the client if the employee was a participant with the predecessor employer, the answer was no (I need to get more info as to why he was not a participant, maybe he never worked 1000h)

Any cites would be really appreciated.
Thank you,

What you want to see first are the terms that provide for past service to be recognized. The regulations under section 401(a)(4) of the tax code address imputed sevice credit.