Imagine you are a junior analyst at a Mumbai-based brokerage, tasked with rebalancing a client’s liquid fund portfolio. You notice that market participants are aggressively selling short-term Treasury Bills (T-Bills) following a hawkish signal from the Reserve Bank of India. While the client expects a fixed return from the maturity value of the bills, the current market price is dipping, creating a disconnect between the face value and the secondary market reality.
Understanding why these prices move is critical for accurately marking-to-market a portfolio that holds these instruments before their maturity date.
Treasury Bills function on a pure discount basis; they do not pay periodic interest. Instead, the return is derived from the difference between the discounted purchase price and the fixed redemption value at maturity. Because the face value is locked, the only variable that adjusts to reflect changing interest rates is the price of the instrument itself.
When market interest rates rise, the yield demanded by investors increases, forcing the price of existing T-Bills to fall to maintain parity with new, higher-yielding issues. Conversely, if rates soften, T-Bill prices appreciate, offering capital gains to current holders.
For an analyst, this inverse relationship is a foundational pillar of fixed-income valuation. If you are managing a portfolio with a short horizon, a sudden hike in the repo rate can result in unrealized mark-to-market losses even on ‘risk-free’ government paper. For instance, consider a 91-day T-Bill with a face value of ₹10,000 trading at ₹9,800.
If market yields for this tenor jump by 50 basis points due to inflationary pressure, the market price must decline to push the yield up, causing the bill to trade at a deeper discount, perhaps ₹9,785. Your valuation model must reflect this sensitivity, or you risk overstating the fund’s net asset value (NAV) during periods of monetary tightening.
This dynamic highlights why T-Bills are not entirely ‘risk-free’ when held for less than their full term. While credit risk is negligible, interest rate risk—the risk that the market price will fluctuate—is ever-present. Seasoned professionals use this to their advantage by strategically adjusting the duration of their cash holdings based on the central bank’s interest rate trajectory. By anticipating shifts in the policy corridor, you can protect the portfolio from price erosion or capitalize on potential appreciation in the secondary market.
Nuance
Check Your Understanding
A corporate treasury holds 91-day T-Bills currently valued at ₹9,900. If the Reserve Bank of India announces a surprise increase in the repo rate, what is the most likely immediate impact on the valuation of these bills in the secondary market?
An analyst is evaluating a portfolio of 182-day T-Bills. If the analyst expects interest rates to fall over the next month, what is the best strategy regarding these holdings?
This is a companion read for Section 9.8 — Introduction to Money Market from PASS Investment Adviser (Level 1) by Akhilesh Gururani, available on Amazon Kindle.
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