1. The revised exemption claim does not have to take effect until the first payroll period ending on or after the 30th day after the new form is filed. If you follow this practice, employees may have to wait 3 to 4 weeks after they file a change for it to take effect.

2. If an employee files a W-4 and has indicated to you that the number of exemptions shown on the W-4 is false, the W-4 s invalid. In this circumstance you may request a new W-4 with valid info. If one is not provided you should continue to use the previous W-4. If there was no previous W-4, you should withhold at the rate for a single person with no exemptions.

3. A revised W-4 is filed when the employee needs to change the number of exemptions claimed. This generally implies a change in circumstances such as a marriage, divorce, new dependent, the loss of a dependent, a change in income with no withholding requiring more or less withholding, or a change in itemized deductions requiring more or less withholding. It is unlikely that an employee who is making nearly weekly changes in his or her withholding allowances is experiencing changes in as circumstances that frequently. You could inquire about what the change in circumstance is. If the number of allowances claimed is not based on fact, the W-4 is invalid and need not be accepted. In addition, you could inform the employee that there is a $5000 penalty that applies if an employee makes statements or claims withholding allowances on a W-4 that reduces the amount withheld and there is no reasonable basis for those statements or allowances. There is also a criminal penalty for supplying false or fraudulent information on a W-4 or failing to supply information that would increase the amount withheld.