There is a difference in the instructions for the Form 5500 between
Line 5 Total number of participants at the beginning of the plan year
Line 6g(1) Number of participants with account balances as of the beginning of the plan year (only defined contribution plans complete this item)
The 2023 instructions for the 5500 line 5 [lightly edited] say: "
For pension benefit plans, âalternate payeesâ entitled to benefits under a qualified domestic relations order are not to be counted as participants for this line.
For pension benefit plans, âparticipantâ for this line means any individual who is included in one of the categories below:
1. Active participants (i.e., any individuals who are currently in employment covered by the plan and who are earning or retaining credited service under the plan). This includes any individuals who are eligible to elect to have the employer make payments under a Code section 401(k) qualified cash or deferred arrangement.
2. Retired or separated participants receiving benefits
3. Other retired or separated participants entitled to future benefits
4. Deceased individuals who had one or more beneficiaries who are receiving or are entitled to receive benefits under the plan. "
The 2023 instructions for the 5500 line 6g(1) say: "Line 6g. Enter in line 6g(1) the total number of participants included on line 5 (total participants at the beginning of the plan year) who have account balances at the beginning of the plan year. Enter in line 6g(2) the total number of participants included on line 6f (total participants at the end of the plan year) who have account balances at the end of the plan year. "
Clearly Line 6g(1) is counts either a subset or all of the participants reported on Line 5. Participants who are eligible to defer but who do not have a balance at the beginning of the plan year are NOT included on Line 6g(1), but they ARE included on Line 5.
The Form 5500-SF instructions are the same where Line 5a is the same as the Form 5500 Line 5 and Line 5c(1) is the same as the Form 5500 Line 6g(1).
Note there is an EFAST2 edit check which may be contributing to the confusion:
"Z-007 - WARNING - Fail when the total participant BOY count on Line 5 of the Form 5500, Line 5a of the Form 5500-SF, or Line 5a(1) of the Form 5500-EZ of the current submission does not match the total participant EOY count on Line 6f of the Form 5500, Line 5b of the Form 5500-SF, or Line 5b(1) of the Form 5500-EZ from the previous year's submission."