here's abc's chuck sivertsen. >> reporter: comedian dave chappelle is using his fame to help dayton,ting a free concert sunday to benefit victims and survivors of the august 4th rampage that left nine dead and more than two dozen injured. >> dayton is strong. there was 120,000 of us here. >> reporter: chappelle grew up in yellow springs, ohio, about 20 miles east of dayton, and still lives there. immediately after the shooting he reached out to the city's mayor asking how he could help. >> at the least we can do, dave, is we have declared it dave chappelle day. >> reporter: the event titled "gem city shine" featured both local talent as well as entertainment from across the country. concertgoers were also able to donate to the oregon district business association, helping local businesses recover. >> it is unfortunate how it came about, but i'm very excited to be here. it's good to be back home in the gem city and have and show the support for our city. >> reporter: everyone is being encouraged to shop at stores and dine at restaurants in the area. chuck sivertsen, abc news, new york

abc's chuck sivertsen has the details. >> as he traveled back to washington on sunday, the presidentnot concerned about the strength of the u.s. economy. >> we have the strongest economy by far in the world. >> reporter: his top economic advisers seem to agree. >> i think we're in pretty good shape, and i want to just say, you know, we should not be afraid of optimism. >> reporter: but stalled trade negotiations with china is rattling wall street. the stock market seeing its biggest one-day drop of the year last wednesday. >> the economy is in a very risky place right now. and every day that goes by, donald trump makes it worse. >> reporter: the president saying china is ready to make a deal, but he's not there yet. >> i mean, if i wanted to make a bad deal and settle on china, the market would go up. but it wouldn't be the right thing to do. i'm just not ready to make a deal yet. china would like to make a deal, i'm not ready. >> reporter: last week's inverted yield curve, when the yield on long-term bonds dips below the yield on short-term bonds, is seen by many economists as a pre