What is the purpose of IRS letter 4464c?

IRS letter 4464C is a notice sent to taxpayers to inform them that their tax return is under review. The letter indicates that the IRS requires additional time to process the return, usually due to issues such as discrepancies or the need for further verification of information. It typically reassures taxpayers that they do not need to take any action unless further communication is received. The letter also provides an estimated timeframe for when taxpayers can expect to receive a resolution.