The point
The rupee falls when more dollars are demanded than supplied at the current price. Oil importers, foreign holders selling Indian securities and borrowers repaying dollar debt create the demand. Exporters, remittances, inflows and the RBI's reserves create the supply. When demand outweighs supply, the price of a dollar in rupees rises until the two sides match. The RBI can slow that move by selling dollars, at a cost it pays out of reserves.
What sets the exchange rate
The exchange rate is a price like any other. It is the number of rupees that one dollar costs at a given moment. Every buyer who needs dollars pushes it up, and every seller who brings dollars pushes it down. Nobody sets it by decree, and no single buyer decides it. On a day when buying outweighs selling the rupee weakens, and on the opposite day it firms.
Who is demanding dollars
Oil importers come first. India buys most of its crude abroad and pays for it in dollars, so a higher oil price means more dollars needed for the same cargo. On 28 September 2026, Brent crude futures traded at $108.04 a barrel, up 3.57 percent on the day (PTI via ETV Bharat, read 29 September 2026).
Foreign holders of Indian shares and bonds come second. When they sell, they convert the rupee proceeds back into dollars. That conversion is demand for dollars, and it lands on the same day as the selling.
Companies repaying dollar loans come third. A borrower with a dollar instalment due buys the dollars on the market, whatever the exchange rate is that day.
The same PTI report names the trigger for that Monday. The US rejected an Iran deal proposal, which lowered hopes of the Strait of Hormuz reopening. Global equities fell, US Treasury yields rose and the dollar index stood at 101.12. The rupee closed at 96.03 per dollar (provisional), 28 paise weaker than the previous close.
Who is supplying dollars
Exporters supply dollars. A software company or a pharma maker that bills abroad sells those dollars for rupees to pay salaries and suppliers at home. Workers abroad who send money home supply dollars too. So do foreign investors who are buying Indian assets rather than selling them.
The central bank is the last supplier. It holds a stock of foreign currency, and it can sell from that stock when the market needs more dollars than it is getting. The forex reserves explainer covers what those reserves are and what they are for.
What the RBI does about it
Reuters reported on 28 September 2026 that persistent RBI intervention had contained the pressure on the rupee. The central bank also used sell-buy swaps to draw excess rupee liquidity out of the banking system. The one-year dollar-rupee forward yield rose as much as 28 basis points in three sessions to 3.50 percent (Reuters via Business Recorder, read 29 September 2026).
Intervention slows the pace of a move, and the level stays with the market. A central bank that sold dollars until the rate stopped moving would empty its reserves in the attempt, and the market knows that. The RBI sells dollars to smooth a fall, and the price still ends up where demand and supply put it.
What that defence costs
The cost shows up in the reserves. India's forex reserves fell by $14.881 billion to $765.901 billion in the week ended 18 September 2026, according to RBI data reported by PTI. Foreign currency assets, the largest part, fell by $14.816 billion to $630.980 billion.
At the rate of 96.03 per dollar, $14.881 billion is about ₹1,42,900 crore. That figure overstates the sales. The same report notes that reserves in dollar terms include valuation effects from the euro, pound and yen the RBI holds. So the fall combines dollars sold with currency moves, and the RBI data does not split the two.
The reserves are large. Even so, every dollar sold to slow a fall is a dollar unavailable for the next one. That is why intervention buys time while the pressure behind it stays.
What a weaker rupee does to a portfolio
A weaker rupee touches each part of a portfolio through a different mechanism.
In the equity sleeve, importers pay more rupees for the same dollar-priced input, which presses their margins. Exporters earn dollars that convert into more rupees, which helps their revenue. An index holds both kinds of company, so the net effect depends on the weights.
In any holding priced in dollars, the rupee value moves with the exchange rate on top of the asset's own price. Take a ₹5 lakh position in a dollar-priced asset. On 28 September 2026 the rupee went from 95.75 to 96.03 per dollar, a change of 28 paise. Divide 28 paise by 95.75 and the move is 0.29 percent. On ₹5,00,000 that is about ₹1,462 of change from the currency alone, before the asset itself moved at all.
Gold is priced in dollars globally. A weaker rupee lifts its price in rupees when the dollar price stays put. The mechanism runs in one direction and says nothing about where either price goes next.
What the equity market has that crypto does not
Equities and crypto face the rupee differently. An Indian company earns and reports in rupees, and the RBI defends the currency it reports in. A crypto asset is priced in dollars across the world's venues. The rupee price an Indian holder sees is that dollar price multiplied by the exchange rate.
So a rupee holder of crypto carries the currency move in full and has no central bank standing behind it. On a day when the dollar price of Bitcoin is flat and the rupee falls 0.29 percent, the rupee price rises 0.29 percent. On a day when the rupee firms, the reverse holds. The two effects add together, and neither is a forecast.
What a holder does with the number
A currency headline is a reason to look at the written allocation, and a poor reason to change it. Check what share of the portfolio is priced in dollars, directly or through the companies held. Check whether that share still matches the weight the mandate set.
Qatobit's QSI indices rebalance monthly on a documented methodology. A rebalance checks the weights against the rules, whatever the exchange rate did that month.
Read the rupee-portfolio effect of a hawkish central bank for the rate side of the same story. A crypto index holds a written set of assets on a written schedule, which puts the currency question inside the allocation and out of the daily news.
The exchange rate matters in proportion to how much of a portfolio sits in dollar-priced assets at all.
Frequently asked questions
Why is the rupee falling?
The rupee falls when more dollars are demanded than supplied at the current price. Oil imports, foreign selling of Indian securities and dollar debt repayments create demand. Exports, remittances, inflows and RBI reserve sales create supply.
What happens when the rupee falls?
Anything priced in dollars costs more rupees. Importers face higher costs, exporters earn more rupees per dollar, and a dollar-priced holding gains rupee value from the currency alone. On 28 September 2026, a 28 paise move was 0.29 percent.
Does the RBI control the rupee?
The RBI intervenes and does not fix the rate. It sells dollars from its reserves to slow a fall. The reserves fell $14.881 billion to $765.901 billion in the week ended 18 September 2026, and that figure includes valuation effects.
Is a weak rupee good for exporters?
A weaker rupee raises the rupee value of dollar revenue, which helps an exporter's earnings. It also raises the rupee cost of any dollar-priced input the exporter buys. The net effect depends on how much of each the company has.
How does the rupee affect crypto held in INR?
Crypto is priced in dollars across global venues. The rupee price is the dollar price multiplied by the exchange rate. A weaker rupee raises the rupee price when the dollar price is unchanged, and a firmer rupee lowers it.
Crypto investments are subject to market risk. Not financial advice.
“A better allocation begins with a better explanation.”
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