Yes in that Mizuho might put more money into Nikko Cordial, but only after Nikko's legal and regulatory issues get resolved. The decision regarding delisting Nikko from the Tokyo Stock Exchange (where its ordinary shares trade under symbol 8603) will come in mid-March.
And yes in that Mizuho is currently re-organizing its existing securities business, and plans to merge its two largest brokerage subsidiaries next year. The Japanese financial behemoth says strengthening its ties with Nikko Cordial is part of this process.
But the "no" in this equation is that Mizuho might not simply buy all of Nikko because it wants Citigroup (C) to remain in the picture. Citigroup owns a chunk of Nikko. And Mizuho would want to maintain complimentary ties to Citigroup's overseas (outside Japan) business. That doesn't mean Mizuho won't eventually buy Nikko -- I've been among those thinking in might for several years now -- but the Citigroup factor has to be considered.
In fact, Citigroup might invest more in Nikko as well (after reducing its stake over the past couple of years).
This could break any one of several ways. Some good. Some bad. Let's stay tuned.