The market is off to a bumpy start for the short holiday week, with the Dow Jones Industrial Average (DJINDICES:^DJI)bouncing around the chart all day and sitting just under breakeven as of 2:35 p.m. EDT. Most of the index's 30 member stocks are falling on the day. Merck (NYSE:MRK) is among the Dow's top winners with a 0.8% gain. Meanwhile, Boeing (NYSE:BA) bottomed out on the index with a nearly 1% drop. Let's catch up on what you need to know.

Boeing vies for South Korea's contract

Boeing's KC-46 tanker. Source: Boeing Media.

Boeing's is bidding for a South Korean contract worth $1.4 billion to deliver tankers capable of refueling military aircraft in flight. South Korea opened for bidding back in March, reportedly pitting Boeing's KC-46 tanker against the A330 from longtime rival Airbus and the B767-300ER from Israeli Aerospace Industries.The South Korean government expects to decide on a winner later this year, and the deal could be another big win for Boeing's KC-46, 179 of which are being delivered to the U.S. Air Force under a 2011 contract.

It's also a chance for Boeing to jump back into the South Korean military market after abruptly missing out on a nearly $8 billion fighter aircraft deal last year. Seoul spurned Boeing's F-15 Silent Eagle after judging the warplane lacking in necessary stealth capabilities, dealing a big blow to Boeing's hopes for a big contract to revitalize its sluggish military aerospace division. The segment saw its contract backlog slide by more than 1% last quarter, with its operating margin decreasing by 1.1% year over year.

Commercial aerospace still drives Boeing's results -- and that segment has been flying high for the company -- but finding new avenues for growth in the military aerospace arena in the current climate of budget cuts would boost the company's investors, who have watched this stock slide by more than 5% to date in 2014.

Meanwhile, European regulators accepted the Merck's submission for approval of its experimental melanoma drug MK-3475. The PD-1 antibody was accepted for review by the FDA in May, and Merck investors need to keep both eyes locked on this drug's outcome.

MK-3475 is one of the biggest blockbuster candidates in the company's pipeline. Merck has already established agreements to investigate the drug in testing with other leading pharmaceuticals, pushing analysts to peg peak sales at up to $3 billion if it is approved. All odds are on that approval, as MK-3475 has performed well in clinical trials and earned a breakthrough therapy status from the FDA during its clinical run. If all goes as planned, this drug could be a huge breath of life into Merck's lagging sales, which have taken patent cliff-related hits lately in falling by more than 3% year over year in its last quarter.