A quick Google found two:
https://www.theguardian.com/world/2014/aug/07/obama-tax-inve...
https://www.reuters.com/article/us-obama-financials/obama-th...
Not sure this will support the original commenters point, as these "threats" have a basis in reality and appear to be good causes unlike Trump's, but these are "threats" by Obama at least according to the journalists involved.
Edit: why the downvotes? I am showing that the Trump supporter above is full of shit, Obama's "threats" were for good causes