Yahoo showed over 1 million shares traded on the 19th and over 2 million on 20th ... this doesn't show in their history, but it did in the daily totals. I think they placed it in large blocks, and it is getting spread around now. They should have done it right after XDivvy, and I believe they did.
If you are talking about the 2,000,100 shares mentioned in the S-3, those are the shares of MTGE that were held by ACAS. When sold, the proceeds go to ACAS not MTGE.
In fact, those shares were sold on 9/7. From a SC 13D filing on 9/12: "On September 7, 2012, ACAS sold 2,000,100 shares of the Issuer’s Common Stock in a registered public offering."
Included in the previously mentioned S-3 filing was also an unspecified number of common and preferred shares that could be offered by MTGE. If those are SPO'd, you'll see a press release and other documents filed with the SEC.