What Are Overnight Funds in Debt Mutual Funds?

At the end of every business day, Indian corporate treasuries, large institutions, and an increasingly aware set of individual investors face the same practical problem: what to do with money that will be needed tomorrow morning. It is too short a window for a fixed deposit. Too risky to leave in an account that earns nothing meaningful. Too brief for even the most conservative equity allocation to make sense. Overnight funds are the answer to this problem.

They are the most conservative category within India’s debt mutual fund spectrum, defined by a single operational rule that is also their most compelling feature: every security in the portfolio matures within one business day. This article explains how that rule shapes everything about overnight funds, from their near zero risk to their practical uses and their taxation.

SEBI’s 2017 categorisation circular divided debt mutual funds into 16 distinct sub categories, organised along the dimension of maturity. Overnight funds occupy the extreme conservative end of this spectrum. They are immediately below liquid funds, which hold instruments maturing within 91 days.

The entire debt fund universe runs from overnight securities on one end to bonds maturing beyond 7 years on the other. Every step further along the maturity spectrum brings progressively more interest rate risk and potentially more credit risk, but also potentially more return. Overnight funds sacrifice both the extra return and the additional risk. Their defining characteristic is stability, not yield.

As a regulatory category, overnight funds were formally introduced in 2018 as part of SEBI’s mutual fund reclassification initiative. Before that, the concept existed informally within liquid funds and money market schemes, but there was no separate standardised category with a strict one day maturity mandate. The formalisation gave investors and fund managers a clean, rule based vehicle that could be used without any ambiguity about the risk profile of the underlying portfolio.

Debt Fund Category	Maturity Profile	Relative Risk Level
Overnight Fund	Instruments maturing in 1 business day only	Lowest in entire debt fund universe
Liquid Fund	Instruments maturing up to 91 days	Very low. Second lowest.
Ultra Short Duration	3 to 6 months Macaulay duration	Low
Low Duration Fund	6 to 12 months Macaulay duration	Low to moderate
Short Duration Fund	1 to 3 years Macaulay duration	Moderate
Long Duration Fund	More than 7 years Macaulay duration	High

SEBI’s definition of an overnight fund is precise: it is an open ended debt scheme that invests in overnight securities, meaning instruments with a residual maturity of exactly one business day. The fund manager cannot hold any instrument that matures beyond the next business day. This constraint eliminates the two primary risks of debt investing in a single rule.

The instruments that meet this one day maturity requirement in the Indian market are primarily Tri Party Repos, commonly known as TREPS. A TREPS is a collateralised borrowing and lending transaction that runs from one business day to the next, with government securities used as collateral. Because government securities back the transaction, the credit risk is essentially negligible.

Other instruments that overnight funds may hold include overnight government repo agreements, call money instruments between banks, and treasury bills purchased with exactly one day to maturity. The common thread across all of these is that they are short, secured, and settle the following morning.

The daily mechanics work as follows. At the start of each business day, the fund’s assets are effectively in cash, because all of the previous day’s holdings have just matured and been repaid with interest. The fund manager then reinvests that cash into a fresh batch of overnight instruments.

Those instruments earn interest through the day and into the night, and the following morning the process repeats. The portfolio therefore turns over completely every single business day. This daily turnover is not a trading strategy or an attempt to time the market. It is the operational architecture of the fund, built into its definition.

“An overnight fund does one thing: it earns interest on your money for one day, then reinvests. And then it does it again. Every single business day.”

The Net Asset Value of an overnight fund follows one of the smoothest trajectories in the entire mutual fund universe. Because all holdings mature and are reinvested every day, the NAV simply accumulates the daily interest accrual on the overnight instruments held. There is no mark to market volatility from changing bond prices, no duration risk from interest rate movements, and no credit event risk from a multi month or multi year exposure to a single issuer.

Like liquid funds, overnight funds calculate their NAV every calendar day, including Saturdays, Sundays, and public holidays. Interest accrues even when the market is not open, and that accrual is reflected in the daily NAV. An investor who parks Rs 1 lakh in an overnight fund on a Friday will find a marginally higher NAV on Saturday, Sunday, and Monday morning, as the fund has accrued interest through the weekend.

The NAV growth curve of a well managed overnight fund looks almost exactly like a straight line sloping gently upward over time. The slope of that line corresponds to the overnight interest rate prevailing in the market. When the RBI’s monetary policy keeps overnight rates elevated, the slope is steeper. When rates are cut, the slope flattens. But there are virtually no downward moves in a normal overnight fund NAV, because there is no mechanism by which the portfolio can lose value unless there is a systemic failure of collateralised overnight lending, which has no historical precedent in the Indian market.

Overnight fund returns are determined almost entirely by the prevailing overnight interest rate in India’s money market. The most widely watched reference rate for overnight lending in India is the Mumbai Interbank Offer Rate for overnight maturities and the RBI’s repo rate, which sets the floor for short term lending between banks. Overnight fund yields track these rates closely, typically running within a narrow band around the repo rate.

As of 2025 and early 2026, overnight funds have been delivering annualised returns in the range of 6.3 to 6.7 percent. This is somewhat lower than the 6.5 to 7.3 percent range typical of liquid funds, reflecting the additional maturity and yield that liquid funds can generate by holding instruments for up to 91 days rather than just one day. The return sacrifice in overnight funds relative to liquid funds is the cost of eliminating that additional duration risk entirely.

For context, this 6.3 to 6.7 percent annualised return translates to a daily return of approximately 0.017 to 0.018 percent per day. On Rs 10 lakh parked in an overnight fund for just three days, the return is approximately Rs 510 to Rs 540 before tax. This is small in absolute terms but meaningfully better than leaving the same amount in a savings account at 3 percent, which would earn approximately Rs 247 for the same three days. The advantage of an overnight fund compounds significantly when deployed consistently for weeks or months.

Tri Party Repo under SEBI or TREPS is the dominant instrument held by overnight mutual funds in India and is worth understanding in some depth because it determines both the safety and the return profile of these funds.

A TREPS transaction involves three parties: a borrower who needs cash overnight, a lender who has surplus cash to deploy, and a triparty agent, which in India is the Clearing Corporation of India Limited (CCIL). The borrower pledges government securities as collateral with the CCIL, which manages the collateral on behalf of the lender. The lender provides cash and receives the government securities as security for the loan.

The following morning, the borrower repays the cash with interest and retrieves their government securities. The CCIL manages the entire settlement process and guarantees the transaction, which means neither party faces the risk of the other defaulting without recourse.

For overnight funds, acting as the lender in TREPS transactions is the core activity. The fund lends cash to banks, primary dealers, and other financial institutions that need short term funding, receives government securities as collateral, and earns the overnight TREPS rate on that lending.

Because the collateral is government securities and the settlement is guaranteed by CCIL, the credit risk in these transactions is as close to zero as any financial instrument can be. This is why overnight funds can genuinely claim near zero credit risk: they are not lending unsecured to any corporate, they are lending against government bond collateral through a CCIL guaranteed mechanism.

One of the most practically important features of overnight funds for short term investors is that they carry no exit load at any point. Liquid funds, by contrast, carry a graded exit load for the first seven days after investment, ranging from 0.0070 percent on Day 1 to zero from Day 7 onwards. This difference is small in absolute rupee terms for most retail transactions, but it is significant in principle.

The absence of any exit load in overnight funds means they can be used for investment windows as short as a single business day without any cost penalty. An investor who parks funds on Monday morning and redeems on Monday evening, or who parks on Friday and redeems on Monday morning, pays no exit load.

For corporate treasuries managing daily working capital positions, payroll reserves, or short term tax provisions, this zero exit load at any duration is a critical feature. For individual investors with funds that will be needed the very next day, overnight funds provide a useful return on what would otherwise be completely idle cash.

The cut off time for overnight fund purchases and redemptions, as revised by SEBI effective June 1, 2025, is 1:30 PM for purchases (to receive the current day’s NAV) and 3:00 PM for redemptions. Purchases made after 1:30 PM receive the following business day’s NAV. Redemption requests submitted before 3:00 PM are processed at that day’s NAV. These timings are stricter than for most other mutual fund categories because of the need to settle overnight transactions before the close of business.

Overnight funds are the closest thing to a risk free product in the mutual fund universe, but the qualifier closest is important. The risks that exist in other debt fund categories are genuinely reduced to near negligible levels in overnight funds, but they are not reduced to zero.

Interest rate risk is effectively zero in overnight funds. Because every holding matures the next day, there is no exposure to the multi month or multi year interest rate movements that affect the NAVs of longer duration debt funds. If the RBI raises rates by 100 basis points today, an overnight fund’s portfolio is entirely renewed the next business day at the new higher rate. There is no stranded low yield position that takes months or years to roll off.

Credit risk is close to zero but not mathematically zero. The primary risk would be a failure of the TREPS mechanism itself, meaning a situation in which CCIL cannot guarantee settlement or where the government securities used as collateral lose their value. No such failure has occurred in India’s financial history. The CCIL is a systemically important financial market infrastructure, and its failure would represent a collapse of India’s financial system far broader than a mutual fund risk. For practical purposes, the credit risk in overnight funds is negligible.

Reinvestment risk is a mild but real consideration. Because all holdings mature every day, the fund is compelled to reinvest at whatever the overnight rate is on that day. In a rapidly falling interest rate environment where the RBI cuts rates multiple times in quick succession, the yield on an overnight fund declines almost immediately with each cut, faster than liquid funds or any longer duration fund. Investors seeking to lock in a rate for a period of months or years cannot do so with overnight funds.

Liquidity risk in overnight funds is structurally lower than in liquid funds because the portfolio is entirely cash and near cash every morning. There is no need to sell instruments into a secondary market to meet redemptions, because the holdings have already matured. This makes overnight funds particularly resilient to large simultaneous redemption events of the kind that occasionally stress liquid fund portfolios during year end or quarter end periods.

Overnight funds serve several distinct investor profiles, each with a different motivation for needing this particular combination of safety and liquidity.

• Corporate treasury management: companies that receive large payments into their bank accounts on specific dates, such as collections from distributors, advance payments from clients, or government contract payments, need somewhere to park those funds until they are deployed. Leaving Rs 5 crore in a current account that earns zero interest for three days before it is used for vendor payments is inefficient. Overnight funds provide a return on that money with no lock in and no exit cost.

• Individual investors between investments: someone who has redeemed a mutual fund or sold equity shares and is deciding on the next deployment often parks the proceeds in an overnight fund while they evaluate options. The money earns a return during the evaluation period rather than sitting idle.

• Emergency fund component: while liquid funds are generally more suitable for emergency funds due to their higher yield and instant redemption facility, some investors prefer the ultra conservative overnight fund structure for a portion of their emergency corpus on the basis that it offers the most reliably stable NAV with effectively no credit risk.

• Tax payment reserves: individuals and businesses who set aside money for advance tax payments, GST payments, or other quarterly tax obligations can park those reserves in an overnight fund for the weeks leading up to the payment date. The money earns a return and remains fully accessible when the payment deadline arrives.

• Sweep account substitute: some brokerage platforms and digital banking applications use overnight funds as an automatic sweep vehicle for idle balances. Any cash sitting uninvested in a trading account above a minimum threshold is automatically invested in an overnight fund at the end of the trading day and redeemed the following morning. This gives investors a return on their trading float without any manual intervention.

For investments made on or after April 1, 2023, all gains from overnight funds are taxed at the investor’s applicable income tax slab rate, regardless of how long the units are held. This is the same tax treatment that applies to all debt mutual funds under the amendments introduced by the Finance Act 2023 through Section 50AA. There is no distinction between short term and long term capital gains for overnight funds purchased from April 2023 onwards. Every rupee of gain is added to total income and taxed accordingly.

This tax treatment makes overnight funds broadly equivalent to a savings account or a short term fixed deposit from a tax efficiency standpoint. All three instruments tax their returns at the investor’s slab rate. The advantage of overnight funds over savings accounts is not tax efficiency but return efficiency: the overnight fund earns more before tax, even if the after tax return is taxed at the same rate.

For units purchased before April 1, 2023, the earlier framework may apply depending on the holding period. Under the earlier rules, debt fund gains after three years qualified for a long term capital gains rate with the benefit of cost indexation, which could substantially reduce the taxable gain for long held positions. Most investors in overnight funds are not holding for multiple years, but those who have held pre April 2023 units should consult a chartered accountant to determine the applicable tax treatment.

The IDCW (Income Distribution cum Capital Withdrawal) option in overnight funds pays out accumulated gains periodically. These payouts are added to the investor’s income and taxed at the applicable slab rate in the year of payout. For most investors, the Growth option is more tax efficient because it defers the tax liability to the point of redemption rather than creating a tax event with each dividend distribution.

Tax Scenario	Treatment	Practical Implication
Units purchased on or after April 1 2023	All gains added to total income. Taxed at slab rate regardless of holding period.	Same as savings account interest or FD interest. No capital gains benefit.
Units purchased before April 1 2023 (post 3 years)	Long term capital gains at 20% with indexation under earlier rules.	Consult a CA. Indexation can significantly reduce taxable gain on old units.
IDCW option payout	Dividend income added to investor’s total income. Taxed at slab rate.	TDS may apply if payout exceeds Rs 5,000 per year per investor per fund house.
Budget 2025 rebate (income up to Rs 12 lakh)	Section 87A rebate may make gains effectively tax free for eligible investors.	Retired individuals or low income investors may pay no tax on overnight fund gains.

Overnight Funds vs Liquid Funds vs Savings Account: The Full Comparison

Feature	Overnight Fund	Liquid Fund
Maturity of instruments	One business day only	Up to 91 days
Typical yield (2025 to 2026)	6.3 to 6.7% annualised	6.5 to 7.3% annualised
Interest rate risk	Effectively zero	Very low but not zero
Credit risk	Near zero (TREPS backed by government securities)	Very low (high quality instruments)
Exit load	None at any duration	Graded for first 7 days. Zero after.
Redemption timing	Cut off 3:00 PM. Funds typically next business day.	Cut off 3:00 PM. Instant redemption up to Rs 50,000 available.
Best use case	One to three day parking. Daily treasury management.	One week to three month parking. Emergency fund component.
NAV stability	Highest in all mutual fund categories	Very high. Slightly more variation than overnight.

Feature	Overnight Fund	Savings Account
Return (2025 to 2026)	6.3 to 6.7% annualised	2.5 to 4% per year depending on bank
Capital safety	Market linked. Near zero credit risk but no guarantee.	Guaranteed by bank. DICGC insured up to Rs 5 lakh.
Tax on gains	Slab rate on all gains (post April 2023 units).	Interest taxed at slab rate. TDS at 10% above Rs 10,000 per year.
Minimum to invest	As low as Rs 100 on most platforms.	No minimum. Balance can be zero.
Accessibility	Next business day redemption. Cut off at 3:00 PM.	Immediate. ATM or transfer any time.
Exit cost	None.	None.
Weekend accrual	Yes. NAV grows daily including weekends.	Yes. Interest accrues daily, credited monthly or quarterly.

Because SEBI’s definition restricts all overnight funds to the same one day maturity universe of instruments, the investment mandate is nearly identical across fund houses. The portfolio of one overnight fund and that of another from a different AMC will look remarkably similar: predominantly TREPS, with some overnight repo and call money positions. This uniformity means the factors that differentiate overnight funds from each other are narrower than in most other fund categories.

• Expense ratio: since all overnight funds essentially do the same thing and earn similar gross yields, a lower expense ratio directly translates to a higher net return for the investor. Even a difference of 0.05 percent in expense ratio compounds meaningfully over time if the fund is used regularly. Always check the expense ratio of the direct plan versus the regular plan, and use the direct plan when investing on platforms that support it.

• AUM and fund house stability: larger overnight funds from established AMCs tend to have better operational infrastructure for managing daily rollovers efficiently. They also face less liquidity stress in the event of large redemptions because a Rs 20,000 crore overnight fund can absorb a Rs 500 crore daily redemption far more smoothly than a Rs 200 crore fund. Look for overnight funds with at least Rs 2,000 to Rs 5,000 crore in AUM.

• Portfolio quality disclosure: even within the near zero risk TREPS universe, it is worth confirming through the monthly factsheet that the fund is indeed holding only overnight TREPS and similar instruments, rather than any other slightly longer dated papers that might have crept into the portfolio near the boundary of what is permitted.

• Platform compatibility: some direct equity trading accounts and brokerage platforms offer seamless transfer between a trading account and an overnight fund, which enables the automatic sweep functionality described earlier. If you want to use overnight funds this way, check whether your primary platform supports this integration before choosing a specific fund house.

Overnight funds are the most conservative instrument in the mutual fund universe. They carry effectively zero interest rate risk and negligible credit risk by virtue of holding only instruments that mature the very next business day, predominantly government security backed TREPS transactions. Their NAV grows smoothly every day, their returns track closely with prevailing overnight rates in the money market, and they impose no exit load at any duration.

They are not a wealth creation tool. The 6.3 to 6.7 percent annualised return, while better than a savings account, is not going to build the corpus needed for retirement or a child’s education. They are a cash management tool: the correct answer to the question of what to do with money you need tomorrow, next week, or next month that is currently sitting idle and earning nothing.

For most retail investors, liquid funds are the more practical choice for parking idle funds because of the higher yield and the instant redemption feature up to Rs 50,000. Overnight funds earn their place in portfolios where the investment horizon is literally one to three days, where absolute capital stability matters more than a few basis points of additional yield, or where the graded exit load of a liquid fund in the first seven days creates an operational complication. For everything else, they are simply the safest place your money can spend the night.