Hello.When brokering a private art sale between buyer and seller, the total dollar amount of the transaction passes through my bank account.I ultimately pay out 90% of that amount to the seller, leaving 10% as my actual revenue in the transaction.

With respect to my net revenue, is there anything I need to do or be aware of for this transaction beyond keeping clear records of 1099s or k-1s issued by me to the seller so that at the end of the year it's clear what my net revenue is versus the vast sums passing through my bank account? Thank You!-

Sure. Just keep good records of what you shelled out as well as what you received.
Many types of businesses have this situation.

(On a bit of a side note, also make sure that all parties know that all accounting will be above board, including things like 1099s. Some are expecting otherwise.)

Yes first no checks, "brokering" is a common scam. They send you money, you send the 90 percent to find out the money you got is fake. After that you owe the bank back the money.

Normally you don't take all of the funds, but merely have the 10 percent paid to you.

There's also money laundering done this way....
I wasn't going to get into all the scams, not know what your story is.

Think about this.. why would two people who don't know you from Jack... trust you an individual with their money? Would you? I certainly wouldn't. There are plenty of well known LEGAL escrow places without putting trust in an unknown individual. I see scam written all over this...