I am US citizen leaving abroad. My mother sold some property and gave me a gift of
90000 dollars. I want to wire the money to the states and establish a stock
Brokerage account and buy USA stocks.
My mother is not USA citizen.
Do I have any tax obligations for the money I have received?

There are NO U.S. tax liabilities for you (since it was a gift to you) or for your mother (because she is not a U.S. citizen).

However, when you wire the money, you may trigger an audit by the IRS, who will want to know from WHERE did you get the money.

If you can show the IRS the cancelled check or money transfer paperwork, that will satisfy the audit.

Yes, as AtlantaTaxExpert said you don't pay any gift tax because in the U.S, the person who receives a gift does not pay the tax. In the U.S. only the donor has gift tax liability. And since your mother is not a U.S. citizen or resident (does not have SSN or ITIN), then she does not have any gift tax liability. In short, there is no tax liability.

However, since it is coming from a foreign country, the IRS wants to make sure that it is a actually a gift. So you must file File 3520 Annual Return To Report Transactions With Foreign Trusts and Receipt of Certain Foreign Gifts if the amount in 2007 is more than $13,258.
You can download the form 3520 Internal Revenue Service (http://www.irs.gov) and read the instructions.

You may have to file another form if you have bank account or other accounts in a foreign country and at any time in the year the balance was more than $10,000. This can happen if your mother transferred the amount in your foreign account. Then you must complete Form TD F 90-22.1 and File with the Department of Treasury by June 30, 2008. The Form TD F 90-22.1 can be download from: Internal Revenue Service (http://www.irs.gov).

MukatA:

Exceptionally well documented. I knew about Form 3520, but the banks make it a point to inform the customers of that filing requirement when the money is transferred in, so I normally do not bother to cover that part.

I must admit that I did not know about the $10,000 balance in a foreign account requirement. We learn something new every day.

I'm selling a property overseas and bringing the money to the USA, does anybody knows what kind of tax is this money have to pay?

Did you eve get an answer in this site? I have the same situation you did! Thank you

did you eve get an answer in this site? I have the same situation you did!! Thank you

I see you also posted this as a separate question - answer is provided here: https://www.askmehelpdesk.com/taxes/bringing-money-back-usa-667526.html