I have a SMLLC and do enough trading every day to qualify as a trader under 475. But I cannot find a way to enter trading income from 1099B in Turbotax and differentiate it from other 1099B personal investment income
You're going to need to file a schedule C as a trader. If you have not made your 'Mark to Market' election yet then you need to do so before you can get regular income treatment for your losses. If you have already made the election then you can enter your trades directly into form 4797 to get regular income treatment for them.
Here is a TurboTax article on making these entries.
Thanks. I have not made the "mark to market" election yet. My problem is that I have several 1099B - only one of the brokerage accounts is specific to trading (business income). Rest are all personal investment income. Line 16 in Schedule D shows both trader and investor transactions, how do I separate them out using Turbotax? I cannot enter 1099B under "Business income", neither can I specify under income, that this particular 1099B is from business/ trading
Since you haven't made the election yet then you don't need to separate them out for this year for tax purposes. For informational purposes going forward you will have to go line by line through your 1099-B and differentiate the transactions.
Also for this year you will need to mail in your return with your election if you want to take it for future years.
If you can't get separate statements in future years for your business and personal investments then you will be stuck going line by line for future tax returns so you may want to work with your broker to get separate 1099-Bs for future years to streamline your tax filing.