That is the original rumour. In spite of the "confirmed" title, it (and every other news piece like it that I have seen) is entirely based on that phrase spoken by the OKCoin tech guy in that interview. Note that he did not say that the fund invested in bitcoin or was going to trade bitcoin, and said "on our platform" rather than "at our exchange".
What else and how often do they have to say it? And what else should they trade? Ripple? Litecoin? You dont really think they Start their own Platform?
Only thing unknown is the Name of The company and with how much they will trade