Google, which has a 5 percent stake in Time Warner's AOL division, has the option to sell it beginning Tuesday.
Google got the stake in AOL through a 2005 deal with Time Warner under which Google invested $1 billion.
According to a Time Warner regulatory filing, Google can sell that stake if it wants, with Time Warner, which owns the remaining 95 percent of AOL, getting first crack at buying the shares.
"Beginning on July 1, 2008, Google will have the right to require AOL to register Google's 5 percent equity interest for sale in an initial public offering," the filing said.
"If Google exercises this right, Time Warner will have the right to purchase Google's equity interest for cash or shares of Time Warner common stock based on the appraised fair market value of the equity interest in lieu of conducting an initial public offering."