A buyer rebate is not classified as an income, and no Form-1099 is issued. The best analogy is the rebates you receive on a cashback credit card. The points / cash rebates that you build up on these credit cards are not reported to tax agencies.
You may apply the rebate towards your closing cost as a credit.
Refer to the IRS document regarding commission rebates for additional information.
A payment or credit at closing from Taxpayer represents an adjustment to the purchase price of the home and generally is not includible in a purchaser’s gross income.
In addition, please consult with a tax professional concerning the tax implications of receiving a buyer rebate.