Dear Your Business Credit, My name is Catt, and I'm running a business as a sole proprietor with a DBA. (creditcards.com)
You can apply as a sole proprietor using your Social Security Number. (millionmilesecrets.com)
So you can technically operate as a sole proprietor in all of your businesses and not have to worry about converting passive income into active business income if you are flipping, because only the * intended * flips will be subject to self employment tax and ordinary income. (biggerpockets.com)