I'm not aware of any "number" of trades that would make put a person in the trade or business of securities for their own account. Here is a link to some guidelines:
https://www.irs.gov/taxtopics/tc429.html
It is a high bar to be considered in the trade or business of dealing in securities for your own behalf. Here is a case where the taxpayer was found NOT to be in the trade or business. Read it and compare to your own circumstances
An investor was not a trader in securities because his trading
activities did not have the frequency, continuity, and regularity to
constitute a trade or business and the long holding periods showed that
he was not seeking to profit from the swings in the daily market.
Endicott v. Comm'r, T.C. Memo. 2013-199 (8/28/13).
There is no "bright line test"...so be informed and beware that it is a high hurdle to be considered in the trade or business of securities trader for your own account.
**Disclaimer: Effort has been made to offer correct information; but due to the discussion forum limitations, the poster disclaims any legal responsibility for the accuracy of the poster's response**
