Dismissing speculation, Tepper told CNBC's "Squawk Box" as part of a wide-ranging interview, "People probably smoke a lot of marijuana out in your viewing audience and people on Twitter, because I don't understand where stuff comes from."
SunEdison shares surged 5 percent late Thursday on an unsubstantiated rumor spread via Twitter that said Tepper may take a position in the renewable energy company.
The stock was down more than 7 percent late morning Friday.
"We haven't had any big positions in my book for a year. Really, truly there must be some really good 'ganja' coming into this country," said Tepper, founder and president of Appaloosa Management, which has more than $20 billion in assets under management.
In Friday's CNBC appearance from Carnegie Mellon University in Pittsburgh, he also talked about the upcoming Tepper Quadrangle on campus as well as the broader stock market and General Motors.
GM is among the top stock holdings for Appaloosa, which owns about 18.7 million shares of the automaker, according to the hedge fund company's latest 13F filing. With GM trading near $35 a share early Friday, Tepper's stock was valued at around $650 million.
General Motors CEO Mary Barra is doing a "really good job," he said. "We did a deal with them, which I think gave them a little leeway to not have other people bother them, activist-type people bother them. It's really got its act together. To tell you the truth, I don't think the market is really recognizing it yet."
The "deal" Tepper was referring to involved GM agreeing earlier this year to launch a $5 billion buyback and put forward plans for capital allocation. Appaloosa was part of an investor group that had pressured the automaker over its balance sheet.
On the overall stock market, Tepper told CNBC on Friday that if there were a "magic formula" for U.S. stocks, it would be China heavily easing its "much too tight" monetary policy. He said he's still pretty cautious about the market.
Tepper also touted Friday on CNBC the successful partnerships that Carnegie Mellon University and the city of Pittsburgh have with major tech companies.
"Google has a major campus here [in Pittsburgh]. Apple is starting to build a major campus," he said. "The hottest companies in the tech arena ... have very big presences in Pittsburgh. And with this university, they know the secret so to speak."
Tepper got his MBA at Carnegie Mellon and has donated more than $100 million to the school, which was breaking ground Friday on the Tepper Quadrangle, a project to bring a new university welcome center and new homes for the Tepper School of Business and the Swartz Center for Entrepreneurship.
"It's an idea for a new type of interaction of the business school and different parts of this university," he said. "This potential here [at Carnegie Mellon] is nothing short ... of an entrepreneurial venture sort of place and bringing it here."
— CNBC's Laura Petti and Reuters contributed to this report.