News Friday that Microsoft was thinking about entering the music subscription business pushed down rival companies' stock prices, a trend that reversed Monday.

Microsoft, which launched its MSN Music online download store in 2004, told Reuters on Friday that "offering a subscription service was an important step in helping people find and discover great music online."

"We are actively investigating the subscription model, but we don't have anything to share today," Christine Andrews, lead product manager of Microsoft's MSN Internet division said, according to Reuters. "Once we are ready to talk more, we'll let you know."

That hit shares of Apple, Napster, RealNetworks, and Yahoo, all which sell music via download; all but Apple have subscription-based offerings of their own where users pay a flat monthly fee to stream an unlimited number of tracks to PCs, or for an additional fee, load tunes onto MP3 portable players.

Apple, for instance, fell nearly 5 percent Friday, to $35.81. Napster dropped 4 percent to $4.13, RealNetworks ended up at $5.01, or more than 3 percent lower, and Yahoo fell 1.7 percent to $36.81.

On Monday morning, however, the four firms' downward trend reversed. By mid-day, Apple had rebounded nearly 2 percent, climbing back to $36.51, while RealNetworks had increased by .6 percent to $5.04. Napster had bounced back more than 3 percent to $4.26, while Yahoo had climbed 1.6 percent to $37.40, just a few cents off its price before Microsoft said it might move on subscription music.