Post Office vs FD vs Arbitrage Fund: Which one offers best post-tax returns? Compare risk and liquidity before investing

A post office time deposit offering 6.9% interest may appear more attractive than a bank fixed deposit (FD) offering 6.25%. But what if an arbitrage mutual fund delivering a slightly lower return leaves investors with more money after taxes? The answer depends largely on the investor’s income tax bracket and how long the money remains invested.

For investors looking to park ₹5 lakh for a year or longer, the difference in post-tax earnings can be substantial. While post office deposits and bank FDs offer predictable returns, arbitrage funds enjoy relatively favourable tax treatment when held for more than 12 months.

Uttam Agarwal, Chief Business Officer, Bajaj Capital – La Premièr, explains how the three options compare on returns, taxation, liquidity and risk, and why the investment offering the highest post-tax return may not necessarily be the most suitable choice.

Which investment offers better post-tax returns?

The biggest difference between these instruments lies in how their earnings are taxed.

Interest from post office deposits and bank FDs is added to the investor’s taxable income and taxed at the applicable slab rate. This means investors in higher tax brackets retain a smaller portion of their interest earnings.

Arbitrage funds, which qualify for equity-oriented mutual fund taxation, are treated differently. Gains on units held for up to 12 months attract short-term capital gains tax of 20%. For holdings exceeding 12 months, long-term capital gains above ₹1.25 lakh in a financial year are taxed at 12.5%.

“When it comes down to how much of the return you get to keep,” the tax treatment becomes crucial, Agarwal explained.

For illustration, he considered a one-year post office deposit offering 6.9%, a bank FD offering around 6.25%, and an arbitrage fund generating an assumed annual return of 6.5%.

At a 30% tax rate, the post office deposit’s effective return falls to approximately 4.9%, while the bank FD delivers around 4.4%, before cess.

An arbitrage fund, however, could allow investors to retain the entire assumed 6.5% return if they hold the investment beyond 12 months and their eligible long-term equity gains remain within the ₹1.25 lakh annual exemption.

Unlike deposit interest, arbitrage fund returns are not guaranteed.

₹5 lakh investment: How much will you earn after tax?

Consider an investor putting ₹5 lakh into each instrument.

At the illustrative annual rates, a post office deposit earning 6.9% would generate ₹34,500 in simple annual interest, while a bank FD offering 6.25% would generate ₹31,250. An arbitrage fund delivering an assumed 6.5% return would earn ₹32,500.

The table compares approximate earnings after applying the stated tax brackets, excluding cess and surcharge.

For an investor in the 30% bracket, the arbitrage fund could generate approximately ₹8,350 more than the post office deposit and ₹10,625 more than the bank FD under these assumptions.

However, the advantage depends on the holding period.

Agarwal cautioned that redeeming an arbitrage fund at exactly 12 months would result in short-term capital gains taxation. At the assumed 6.5% return, the investor would retain around ₹26,000 after 20% tax, before cess, rather than the entire ₹32,500.

The ₹1.25 lakh exemption is also shared with eligible long-term gains from other equity investments, including shares and equity mutual funds.

Which option offers better liquidity?

Access to money is another important consideration, particularly for investors who may need funds unexpectedly.

Post office time deposits have relatively restrictive premature withdrawal rules. Withdrawals are not permitted during the first six months. If a one-year deposit is closed after six months but before maturity, the post office savings account interest rate, currently 4%, applies.

For two-year and three-year deposits closed after one year, the applicable interest rate is reduced by two percentage points, Agarwal said.

Bank FDs generally offer greater flexibility. Investors can usually close deposits prematurely, although banks commonly impose an interest penalty of 0.5 to 1 percentage point.

Arbitrage funds allow redemptions on business days, with proceeds typically credited within a few working days. Some schemes impose an exit load, often around 0.25%, on early redemptions.

However, unlike deposits, the redemption value of an arbitrage fund fluctuates with market conditions.

Post Office vs FD vs Arbitrage Fund: Which is safer?

For investors prioritising capital safety and predictable earnings, post office deposits have an advantage because of their government backing and known interest rates.

Bank FDs also provide predictable returns. Eligible deposits are insured up to ₹5 lakh per depositor per bank, including principal and interest.

Arbitrage funds invest using cash and derivatives market strategies to capture pricing differences. Although generally considered relatively low-risk among equity-oriented mutual funds, their returns are neither fixed nor guaranteed.

Agarwal also pointed out that higher futures transaction taxes could affect arbitrage fund returns by increasing transaction costs.

For investors able to stay invested for at least a year, Agarwal’s overall preference is post office deposits first, arbitrage funds second and bank FDs third.

However, for those who may need access to their savings sooner, bank FDs and arbitrage funds become more attractive.

The choice ultimately depends on the investor’s tax bracket, investment horizon, liquidity requirements and willingness to accept market-linked returns. A higher post-tax return alone should not determine where the money is invested.