What is NIRP? Negative Interest Rates! Yesterday June 5th, 2014, was historic. It is the first time “official” negative interest rates have been implemented by a central bank. NIRP was implemented yesterday by the European Central Bank on 18 nations. Rates have hit negative territory before a during bidding crisis, and Denmark did it briefly in 2012, but no central bank has done it before in an official capacity. Read more here.