The question is why did you receive income that was separately reported on a 1099.
Generally speaking, everything that your employer provides as compensation for services given should be wages reported on your W-2. If this was a bonus, or something else given in recognition of your service, it should have been reported on your W-2. The proper procedure is to contact the employer first and ask them to issue a corrected W-2 and cancel the 1099. If they refuse to do this, you can report the income using form 8919 with code H. This is for a 1099 that should have been reported as W-2 wages. I believe that in the 1099 interview, there is a box you can check on a page listing special circumstances for, “these were wages from my employer that should’ve been on my W-2.”
The other possibility is that you work in an industry where you receive bonuses directly from the manufacturer of things you sell, rather than from your employer. These are sometimes known as SPIFFs, or performance incentives. For example, you work for an appliance store and you receive regular wage from your employer, and then you receive a bonus check directly from thr manufacturer for their appliances that you sell. The spiff is not considered compensation for work performed, because you are not working for the payer. In this case, the spiff is properly reported as 1099-MISC income that is not related to your regular job.
