NEW YORK, Sept 8 (Reuters) - Boeing Co shares are climbing and helping to limit losses on the Dow and S&P 500 after Ryanair Holdings Plc, Europe's largest low-cost airline, agreed to buy 100 Boeing Co 737 MAX 8 jetliners.
Boeing shares are up 2.4 percent and on track for their biggest daily percentage gain since April. The agreement also includes an option for 100 more planes for a total value of approximately $22 billion.
Boeing's shares are still down 6.4 percent for the year so far, but the stock is not considered overpriced according to Thomson Reuters StarMine's intrinsic valuation model, which estimates the value at $145.41, compared with the current price of $127.64.
Index snapshot at 11:31:
* S&P 500 is falling 3.15 points, 0.16 percent.
* Nasdaq Comp is adding 12.47 points, 0.27 percent.
* Dow industrials are down 11.15 points, 0.07 percent.
* Russell 2000 is adding 2.26 points, 0.19 percent.
* S&P MidCap is down 0.87 points, 0.06 percent.
* S&P SmallCap is up 0.68 points, 0.1 percent. (Editing by Lisa Von Ahn, Chizu Nomiyama and Nick Zieminski)