Moody's Investors Service said it may downgrade Baxter's credit rating because of the debt Baxter will take on as part of the deal. Moody's currently rates Baxter's credit at 'A3'. That rating is investment grade and is four notches above non-investment grade or "junk" status.
The Wall Street Journal reported last month that Baxter was negotiating to buy Gambro, which is owned in part by Investor AB, the Swedish investment group controlled by the Wallenberg family.
Shares of Baxter fell 58 cents to close at $65.22 Tuesday.