In this scenario, the employee is contributing $123.25 to their 401(k) plan, with the employer matching 100% of that contribution. This means that the total monthly contribution, when accounting for the employer match, would be:
\[ \text{Total Monthly Contribution} = \text{Employee Contribution} + \text{Employer Match} \]
Since the employer matches 100%, the employer contribution will also be $123.25. Therefore, the total monthly contribution is:
\[ \text{Total Monthly Contribution} = 123.25 + 123.25 = 246.50 \]
So, the size of the monthly contribution after the employer match is accounted for is $246.50.