NEW YORK (CNN/Money) - AOL Time Warner Inc. and AT&T Corp. have temporarily suspended discussions of a possible change of ownership of their jointly owned cable and entertainment holdings.

The unit, known as Time Warner Entertainment Co., includes most AOL Time Warner cable operations as well as some of its television networks, Warner Brothers movie studio and HBO. AOL Time Warner owns 74.5 percent of the unit and AT&T owns the remaining 25.5 percent.

AOL and AT&T hired Banc of America Securities in June to decide the valuation of the company, a decision that would have given AOL 15 days to decide whether to sell shares of TWE to the public so that AT&T could sell its shares or to buy AT&T's stake outright. AT&T would have had 20 days to respond to the AOL offer.

But the companies said Tuesday they had agreed to suspend the registration rights process for an undefined "short period of time" so that "the two companies and Comcast Corp. can pursue discussion of an alternative transaction." AT&T has agreed to sell its cable operations, including its stake in TWE, to Comcast.

The two companies said there is no assurance the discussions will lead to a deal, and that they would make no further comment on discussions unless they reach a deal or return to the registration process.

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There is a difficulty in offering shares of the new company to the public, given a weak market for both initial public offerings and cable stocks.

Shares of AOL Time Warner (AOL: Research, Estimates), the owner of CNN/Money, gained 68 cents to $11.58 Monday while shares of AT&T (T: Research, Estimates), a component of the Dow Jones industrial average, rose 60 cents to $9.74, and Comcast (CMCSK: Research, Estimates) was up $2.15, or 11.7 percent, to $20.60.