Opera Software is making another acquisition to build out its mobile advertising business: It has either purchased or is close to purchasing mobile video advertising startup AdColony, according to sources with knowledge of the companies. We’ve contacted both companies asking for comment. Opera spokespeople in the U.S. and Europe have told us that the company will not comment on market rumors, and AdColony has not responded to requests for comment. One source said that they’d last heard the negotiations were nearly complete. The other said the deal had closed at a price in the low hundreds of millions (up to $275 million). Now, we don’t want to downplay the difference between a deal that’s done and almost done, but for what it’s worth, the “not quite done” source did acknowledge that their information might be a little out-of-date, and that a completed deal would be consistent with the timing that they’d be hearing about.