President Obama's 2012 campaign manager is asking top donors to give more money than they did during Obama's first presidential campaign.

Jim Messina has been asking donors to contribute "north of $750 million," according to the Chicago Sun-Times, which is about the amount Obama raised during his first presidential campaign. Some political observers have estimated Obama might need to raise as much as $1 billion this time around.

Individually, top Obama donors are reportedly being asked to donate $350,000 each, divided between Obama's reelection campaign and to the Democratic National Committee, which is $100,000 more than they did on average in 2008.

Messina's donor lobbying is one of the latest signs that, as the 2012 Republican presidential field begins to take shape, Obama is also thinking ahead to his reelection. Earlier this week his campaign settled on a specific building in downtown Chicago for its reelection headquarters. Former members of the White House and DNC are planning to relocate to Chicago for the 2012 race.