The FASB authoritative guidance on fair value measurements defines fair value, provides a framework for measuring fair value, and requires certain disclosures about fair value measurements. The required disclosures focus on the inputs used to measure fair value. The guidance establishes the following hierarchy for categorizing these inputs:

Level 1	—	Quoted market prices in active markets for identical assets or liabilities

Level 2	—	Significant other observable inputs (e.g., quoted prices for similar items in active markets, quoted prices for identical or similar items in markets that are not active, inputs other than quoted prices that are observable such as interest rate and yield curves, and market-corroborated inputs)

Level 3	—	Significant unobservable inputs

There were no transfers of financial assets or liabilities measured at fair value between Level 1 and Level 2 and there were no Level 3 investments during the first six months of either fiscal 2019 or 2018.

At March 31, 2019 and September 30, 2018, Cabot had derivatives relating to foreign currency risks carried at fair value. At March 31, 2019 and September 30, 2018, the fair value of these derivatives was a net liability of $7 million and $18 million, respectively, and was included in Prepaid expenses and other current assets and Other liabilities on the Consolidated Balance Sheets. These derivatives are classified as Level 2 instruments within the fair value hierarchy as the fair value determination was based on observable inputs.

At both March 31, 2019 and September 30, 2018, the fair value of guaranteed investment contracts, included in Other assets on the Consolidated Balance Sheets, was $11 million. Guaranteed investment contracts were classified as Level 2 instruments within the fair value hierarchy as the fair value determination was based on other observable inputs.

At March 31, 2019 and September 30, 2018, the fair values of cash and cash equivalents, accounts and notes receivable, accounts payable and accrued liabilities, and short-term borrowings and variable rate debt approximated their carrying values due to the short-term nature of these instruments. The carrying value and fair value of the long-term fixed rate debt were $670 million and $686 million, respectively, as of March 31, 2019, and $747 million and $742 million, respectively, as of September 30, 2018. The fair values of Cabot’s fixed rate long-term debt are estimated based on comparable quoted market prices at the respective period ends. The carrying amounts of Cabot’s floating rate long-term debt and capital lease obligations approximate their fair values. All such measurements are based on observable inputs and are classified as Level 2 within the fair value hierarchy. The valuation technique used is the discounted cash flow model.