You should use your social security for 2019 since that is what your business is under for 2019, and then for 2020 start using your EIN.
Thank you.
I was concerned that the IRS would have new EIN in their system and kick out my forms filed with old SS# I'm filing for last year.
It would be best to use your company EIN since you have it now. This will help you safeguard your social security number better with respect to identity theft. It won't impact your income tax filings either way.
If you just got your EIN in 2020 and have not yet filed your 2019 tax return for the same business, then you can use the EIN on your 2019 tax return. Here's my view.
Under no circumstances and with no exceptions will I *EVER* give my SSN to anyone. Period. End of Story. They get my EIN or they can seek my services elsewhere.
If you provide your SSN to contractors or clients (basically, people you don't "really" know) and that number gets abused while in the possession of that third party, then there's the risk it will totally ruin your entire life - forever! So there's no way on this green earth I will *EVER* give anyone my SSN when it comes to my business. They get the EIN (and only if they have a legal need for it) or nothing. Any client who has paid my business more than $600 in the tax year does "in fact" have a legal need for it.
Now if the EIN gets abused, that only affects my business. But it's gonna be kinda hard for it to be abused. That's because there are only two entities on this planet that know what SSN that EIN is tied to.... me and the IRS. That's it. So if you have my EIN you have no idea what SSN that EIN is tied to. Makes it harder for you to abuse it.
At best, you "might" be able to open a business bank account with the EIN. But that's only if you can provide the bank the "correct" SSN that EIN is tied to. While I can't say it's impossible, it won't be easy.