NEW YORK ( TheStreet) -- Potential Yahoo! ( YHOO) bidders have been informed of the Internet company's demands for confidentiality that would prevent them from discussing joint bids, Reuters reported, citing several people close to the situation. Yahoo! advisers Goldman Sachs and Allen & Co. informed interested parties this week of a "no cross talk" provision, part of a non-disclosure agreement they must sign to get a look at Yahoo!'s sensitive financial data, the sources told Reuters. Some private-equity firms, which had planned to jointly bid for Yahoo!, have refused to sign the nondisclosure agreement. Since Yahoo! is so big, with a market value of about $20 billion, the only exception to a joint bid would be Microsoft ( MSFT), according to Reuters and The Wall Street Journal. The Journal, citing people familiar with the matter, reported Microsoft was working with private-equity firm Silver Lake Partners and the Canada Pension Plan Investment Board to put together a proposal to buy Yahoo!. -- Written by Joseph Woelfel >To contact the writer of this article, click here: Joseph Woelfel >To submit a news tip, send an email to: email@example.com.