How should I report the return of investment capital for tax purposes if I withdraw my EB-5 application?

You need to consult with a tax expert, but if it is not income, then you may not be subject to income tax but if it is merely a return of your capital. It is not clear whether this would be taxable.

The gift from your parents should comply with U.S. law and the law of the foreign country. You should consult with an accountant about tax issues.

The general rule of taxation process is that you will be taxed from the beginning of the year until the time your withdrawal is processed, the period is considered to be the taxing period when your investment was earning revenue for you. For example, if your fund was invested between January and July before you withdrew it, you would be liable for seven months of the year. Further, the regional center you invested with will provide you, for tax purposes, records of revenue your investment generated. Advisably, you must provide all the relevant information and documents on your investment to the tax specialist who prepares your tax return. This is because the regional center that administered your investment would provide the information about your investment at the end of the year to the Internal Revenue Service. Therefore, be cognizant that you will be liable for taxes for the period when your money was invested.

There should be no tax reporting. It is a return of capital and thus non-taxable.