Wall Street gains as investors hold out hope for a US-Iran deal

STORY: Wall Street's main indexes rallied on Monday, with the Dow gaining more than six-tenths of a percent, the S&P 500 climbing 1% and the Nasdaq adding nearly one-and-a-quarter percent.After a muted start to the day, stocks picked up steam midday after President Donald Trump said Iran wants to make a ceasefire deal, which he said could not include Tehran having nuclear weapons.Still, just the hint of a near-term truce reignited investor optimism, said Kevin Mahn, president and chief investment officer at Hennion & Walsh Asset Management."Each time there is a ceasefire announcement or the prospect for an ultimate resolution in the Middle East go up, well, then you see oil prices come down, inflation forecasts come down, yields come down, and markets start to go back up. And we continue to go back and forth with those two camps each passing day. And until we receive that ultimate resolution, we're not going to receive or see a sustainable recovery in the equities market or the bond markets. But investors believe, in my opinion, that likelihood is high, or else we would see the market selling off much more than they are right now.":: FileThe S&P 500 had fallen as much as 7.8% since the war in Iran began in late February.But by Monday's close, the benchmark index had erased those losses, closing 0.1% higher than its February 27th finish.:: Allogene TherapeuticsStocks on the move Monday included Allogene Therapeutics, which hit its highest level in over two years earlier in the session before ultimately settling 12.5% higher. Investors poured in after interim data from a mid-stage study showed that the company's blood cancer therapy reduced the risk of relapse in patients.Shares of Albemarle, ​the world's largest lithium producer, gained nearly 7% after Oppenheimer raised its price target on the stock.On the flip side, concerns about higher oil prices pressured airline stocks, with United Airlines, Delta and American all seeing losses.