Timothy Geithner, the US Treasury Secretary who proposed an increase to the EFSF at the Ecofin meeting on September 16, said that the sovereign debt pressures and banking strains in Europe were "the most serious risk now confronting the world economy". Larry Summers, Barack Obama's former chief economic adviser who was attending his 20th IMF meeting, said: "I have not been at a prior meeting at which matters have had more gravity."