Shares in the company climbed $26.44, or about 21 percent, to $152.69 before edging back a bit in afternoon trading.
Today's rise is the latest boost in the streaming media software maker's shares, which have climbed about $31, or 27 percent, since last Thursday, when they traded around $114.
RealNetworks' shares were first jump-started last week after the company announced partnership deals with Universal Music Group and Sony in which music fans could use its RealJukebox software to download, play and store songs from Universal's catalog.
The latest move in the stock follows a "strong buy" recommendation and an 18-month price target of $250 from Lawrence Marcus, an analyst with Deutsche Banc Alex Brown.
"RealNetworks is the best pure play to leverage the Time Warner-AOL deal and the expected explosion in the rich media Internet ecosystem," Marcus said.
The company, which is a cross between an infrastructure provider for streaming media and a media company with its content aggregation, advertising and e-commerce model, stands to bridge the gap between narrowband, broadband and enhanced TV, Marcus noted.