Looking at the volume today (over 13m shares) it seems the IPO was executed this morning. That is why the price has been able to continue to climb today back to "normal" territory. Expect further regression to mean up until ex-div date.
Wrong. In fact, this 11M+ unit follow on offering was just priced this evening at $22.85. They will start selling tomorrow and hope to have unloaded all of the units by August 19. There's a good chance that the unit price will drop even further after it goes ex. div. next week.
Do you? Might want to check your Investopedia. IPO refers to any share that is being offered to the public for the first time. It can be a new share issue, or a selling of existing shares not already publicly traded. In this case it is the latter, so there is no dilution to shareholder claim on equity or dist. This is, however, shares added to the publicly traded float.
While you are right that this is current holders selling shares, this was an IPO. IPO stands for "initial public offering". Whenever shares that have never been publicly traded are introduced to the public market, it is an IPO and dealt with as such. NTI is not issuing new shares, so there is no dilution, none the less, the 11.5 million shares in this IPO were not previously publicly traded, but held by an insider and this sale adds them to the publicly traded "float".