While French and British leaders have been high profile, the low-key German chancellor is getting credit for the summit's regulatory focus.
With the dust now settling in London after two days of posturing and hard bargaining, some observers are mischievously suggesting that neither French President Nicolas Sarkozy, with his aggressive push for ending tax havens, nor British Prime Minister Gordon Brown, who unveiled the final communique from the Group of 20, was the summit's driving force.
And no, it wasn't President Obama, either.
Instead, another leader, who kept a much lower profile, can claim considerable ownership: German Chancellor Angela Merkel.
To be sure, she and President Sarkozy teamed up to draw an eve-of-summit line in the sand against a global fiscal boost for the world economy. At at the summit's conclusion, a jubilant Sarkozy said they got more than they could have hoped for.
But while the chancellor appeared almost diffident in the company of her flamboyant French counterpart, many suspect that she was the truly senior partner. Many observers say that the summit would not have had its strong regulatory focus without her.
"She is perceived to be lacking in assertiveness at home, where she faces an election this year, and the G-20 was an opportunity for her to show that she was a world leader," says Thomas Saalfeld, a professor at the University of Kent who specializes in German politics. "From reports back in Germany, she has been successful in positioning herself as one of the three or four people who really mattered at this summit."
The summit may have played to her strengths, he adds. "She is a fixer, an extremely effective politician at sealing deals," he says. "So I suspect that she was really quite important at this summit behind the scenes."
Other analysts have suggested that the difference of opinion between the Franco-German axis and the British-American alliance about delivering a greater stimulus has been overplayed.
Will Hutton, a leading British economist, points out that the German economy has built-in "stabilizers" that automatically release government funds to boost the economy, meaning that country's budget deficit in 2010 will have risen at a greater rate than those of the United States and Britain. "France and Germany really have generous welfare states, and so we shouldn't allow ourselves to forget that," he notes.
"The real surprise of this summit is actually how much has been agreed."
As host, Prime Minister Brown shared the details emerging from the summit.
A package of $1 trillion for the International Monetary Fund and the World Bank was agreed to help struggling nations around the world, announced the prime minister. The measure includes a $500 billion boost in funding for the IMF, $250 billion aimed at developing countries through "special drawing rights," and $250 billion to boost world trade.
Brown also outlined new policies to crack down on tax havens, regulate hedge funds, and rebuild trust in the financial system to "prevent a crisis such as this from happening again."
Greater regulation of hedge funds and credit-ratings agencies is also on the way, as well as $100 billion in aid for the world's poorest countries and a new Financial Stability Board that will work with the IMF to provide an early warning mechanism for the financial system
"This is the day that the world came together to fight back against the global recession, not with words, but with a plan for global recovery and for reform," added Brown.
At her own post-summit press conference, Chancellor Merkel struck a typically sober pose, cautioning that the devil will be in the details of the G-20 deal's implementation.
But, she said, the agreement was "a very, very good, almost historic compromise" that would give the world "a clearer financial market architecture."
Of course, every leader at the summit will be eager to be seen as having helped engineer this outcome, and there is something for everyone in the final package.
China, for example, is on much stronger ground in terms of securing greater voting rights on the IMF after its president, Hu Jintao, committed his country to giving $40 billion worth of extra funds to the fund.
US officials credited Obama with bridging the divide when it came to agreeing on new measures on tax havens.
Television pictures showing a group of backslapping G-20 leaders having an impromptu chat, with Obama reaching out to grasp Lula's hand.
"I love this guy. He's the most popular politician on earth," Obama told his counterparts.