I am now being told that the pledge for trade finance will be larger than thought - $250bn, though as I suggested yesterday, a good chunk will be national efforts that have already been announced.
As my colleague Robert Peston says, the $250bn SDR (Special Drawing Rights) allocation is huge news, and note the significance of the number: that's the maximum increase they could do without the US having to seek approval from Congress.
Congress is relevant to the IMF money as well - the US will have to get congressional approval for its promise to lend more to the Fund, which I am told will be $100bn. But crucially, by long convention the cost will be scored at zero. Which is why the leaders are willing to take Obama's promise on faith.
For more background on the SDR issue, see my article Will the G20 expand the role of the IMF?.
Update 13:14: To clarify the point about the IMF lending and the US Congress: it's all very nerdy stuff, but the US wants to put its money in the IMF by contributing to a multilateral lending facility called the New Arrangements to Borrow.
The Congressional budget office, which determines the cost to the budget of everything the government does, has traditionally scored these contributions at zero cost because the US would effectively be making money available to a triple-A rated institution, the IMF, and getting a claim on all the IMF members in return. Boring, but crucial.