I have seen companies that come out with good news

I have seen companies that come out with good news and the pps goes down. I guess that is what they mean by saying sell on the news and buy the rumor. And on the other hand I have seen companies with bad news go up. So I can not make the judgement whether this is good news or bad news only that it is old news. If Belize comes thru and most feel there is oil in Belize is this considered a rumor? If so buy the rumor which I believe will become a reality. Teco is doing great things now and the company is in good shape now going forward. Go TECO.