Yes, an LLC can invest in stocks and can deduct all expenses related to those activities as business expenses.
You will need to both establish an LLC and then have all of your brokerage statements and stock trades shown as belonging to the LLC using the federal EIN. This involves transferring a lot of your property to the LLC so I would recommend consulting a legal professional both about structuring the LLC as well as making sure that the transfers are smooth.
@Tk44
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