Shares of Dow Inc. and Merck are retreating Friday afternoon, sending the Dow Jones Industrial Average into negative territory. The Dow /zigman2/quotes/210598065/realtime DJIA -3.56% was most recently trading 133 points lower (-0.5%), as shares of Dow Inc. /zigman2/quotes/203121064/composite DOW -4.27% and Merck /zigman2/quotes/209956077/composite MRK -1.23% are contributing to the blue-chip gauge's intraday decline. Dow Inc.'s shares have declined $1.64 (3.3%) while those of Merck are down $2.87 (3.2%), combining for an approximately 31-point drag on the Dow. Other components contributing significantly to the decline include JPMorgan Chase /zigman2/quotes/205971034/composite JPM -2.69% , Pfizer /zigman2/quotes/202877789/composite PFE -2.94% , and Walgreens Boots /zigman2/quotes/203410933/composite WBA -4.70% . A $1 move in any one of the 30 components of the index equates to a 6.78-point swing.