Table:
| December 28, 2019 | Amortized Cost | Gains | Losses | Fair Value |
| --- | --- | --- | --- | --- |
| U.S. Treasuries | $10,458 | $11 | $— | $10,469 |
| Commercial paper | 3,914 | 1 | (4) | 3,911 |
| Corporate bond | 33,867 | 68 | (7) | 33,928 |
| Certificate of deposit | 3,584 | 5 | — | 3,589 |
| Agency securities | 24,408 | 38 | (16) | 24,430 |
|  | $76,231 | $123 | $(27) | $76,327 |
| December 29, 2018 | Amortized Cost | Gains | Losses | Fair Value |
| U.S. Treasuries | $7,997 | $1 | $(1) | $7,997 |
| Commercial paper | 2,296 | — | (1) | 2,295 |
| Corporate bond | 30,833 | 1 | (160) | 30,674 |
| Certificate of deposit | 960 | — | (3) | 957 |
| Agency securities | 8,667 | — | (59) | 8,608 |
|  | $50,753 | $2 | $(224) | $50,531 |
Paragraphs:
Marketable Securities
Marketable securities consisted of the following (in thousands):
We classify our marketable securities as available-for-sale. All marketable securities represent the investment of funds available for current operations, notwithstanding their contractual maturities. Such marketable securities are recorded at fair value and unrealized gains and losses are recorded in Accumulated other comprehensive income (loss) until realized.
We typically invest in highly-rated securities with low probabilities of default. Our investment policy requires investments to be rated single A or better, limits the types of acceptable investments, concentration as to security holder and duration of the investment. The gross unrealized gains and losses in fiscal 2019 and 2018 were caused primarily by changes in interest rates.
The longer the duration of marketable securities, the more susceptible they are to changes in market interest rates and bond yields. As yields increase, those securities with a lower yield-at-cost show a mark-to-market unrealized loss. We anticipate recovering the full cost of the securities either as market conditions improve, or as the securities mature. Accordingly, we believe that the unrealized losses are not other-than-temporary.
When evaluating the investments for otherthan- temporary impairment, we review factors such as the length of time and extent to which fair value has been below the amortized cost basis, current market liquidity, interest rate risk, the financial condition of the issuer, and credit rating downgrades. As of December 28, 2019 and December 29, 2018, gross unrealized losses related to our marketable securities portfolio were not material.
Question:
How is marketable securities classified?
Answer: We classify our marketable securities as available-for-sale.