I'm on a H4 visa right now. My parents wire transferred me over $100k in 2015 to invest real estate. I filed form 3520 for it. We are going to do the purchase soon. The question is if the real estate is to be put under my parents names, do I owe the gift tax since I pay for it? Is there any way to return the money to my parents without the tax since it really doesn't make sense.

If you reported the $100K transfer as a gift on the Form 3520, amend the Form 3520 to show the money for what it is: a business investment that you are managing.