I was told no.
You can call them and will be told only Form 1040 earnings count.
It does not matter about owning other assets.
It is my understanding that ONLY earned income has an affect on your Social Security benefits; all other income such as interest income, royalties, bonus money, etc. will not penalize your SS Income. W-2's count while 1099's do not. Would be a good question to pose to your local Social Security office personnel. It is best to have the real authority answer this one. Good luck.
It won't effect your SS check, but it could effect what you you pay for Your Medicare Part B premium when you turn 65, or on Medicare Disability before age 65. As your income rises, so does the Part B premium. They calculate by looking at your tax return from 2 years back then follow the sliding scale chart. It can go from $134 to $428.60/month. You can check it at Medicare.gov and clicking on what does Part B cost.
One additional point: IF you happen to be on ObamaCare health coverage and are getting a subsidy, you'll need to be careful. When your "income" relating to eligibility for a subsidy is calculated, royalty payments ARE included. That said, royalty payments could quickly make you ineligible for such subsidies and you may have to pay the full premium due to higher overall income.
Bonus money (or even royalties) are defined as "passive income." Only "earned income" is taken into account relative to SSD or straight early SS income. But yes, it can affect your medicaid part B so please talk to someone about that.
Turkey Leg: the additional comments you brought to the table are great - thanks.
I do want to clarify my earlier comment relates to anyone on OBAMACARE/receiving a subsidy. I'm too young for Medicare/Medicaid and know nothing about how a royalty would impact those so your comments bring that to the surface.
I only wanted to call out Obamacare Health coverage with a subsidy - my 1st royalty check now strips away my subsidy. I'll go from $580.00 a month (subsidized) to now $950 a month since gov. will remove subsidy. (and that's just health coverage - no dental/vision!) That said, I just didn't want someone receiving a subsidy to be surprised due to an income increase by a royalty.
Summary: good news! Royalty!!! Bad news...need to pay the government!!! Life is still good.