NEW YORK (TheStreet) -- Merck & Co. (MRK - Get Report) shares are down -1.2% to $56.40 in pre-market trading after being downgraded to "equalweight" from "overweight" by analysts at Morgan Stanley  (MS - Get Report) on Wednesday.

The downgrade comes on the heels of yesterday's news that German drug maker Bayer AG  (BAYRY) had agreed to purchase Merck's consumer care division for $14.2 billion.

The deal makes Bayer one of the largest over-the-counter drug companies in the world as it assumes control of Merck's most popular non-prescription brands.

Must Read: Warren Buffett's 10 Favorite Growth Stocks 

STOCKS TO BUY: TheStreet Quant Ratings has identified a handful of stocks that can potentially TRIPLE in the next 12 months. Learn more.

MRK Chart

MRK data by YCharts

STOCKS TO BUY: TheStreet's Stocks Under $10 has identified a handful of stocks that can potentially TRIPLE in the next 12-months. Learn more.