The ratings agency also assigned a Negative Rating Watch to the firm's notes offering, noting it will resolve this notation as more details of the offering become available.
The firm plans to use the funds to repay outstanding debts and for general corporate purposes.
The firm has not disclosed the amount it is seeking, but said it plans to use the funds to repay outstanding debts and for general corporate purposes.
The company said it will use most of the proceeds to redeem the outstanding $900 million principal amount of its 1.30 percent senior notes due 2017.
Fitch has given the two-year senior notes offering a BBB rating with a Stable outlook.
The 10-year notes were rated BBB by Fitch, which also declared the ratings outlook Stable.
The firm sold three series of senior notes and will use proceeds to repay other outstanding debt.
The firm will use the proceeds along with cash on hand to redeem notes that mature in August.
Thermo Fisher intends to use the proceeds to redeem the outstanding $900 million aggregate principal amount of its 3.20 percent senior notes that mature in March.
Net proceeds from the offering are expected to be $1.98 billion, which will be used to repay part of the financing that went toward Danaher's buy of Pall.
In PNAS this week: genes involved in histone deacetylation in Arabidopsis, effects of pathogenic presenilin-1 mutations, and more.
After a study finds DNA from antibiotic-resistant bacteria in Beijing smog, residents there worry, according to the New York Times.
Canada begins its search for a chief government science advisor, Nature News reports.
A company is using facial recognition tools to identify genetic disorders from pictures, Technology Review reports.