Summary
The Sensex fell 492.70 points to close at 77,235.46 and the Nifty 50 lost 132.75 points to end at 24,154.90 on Tuesday, 18 August 2026, as elevated crude prices and rising West Asia tensions weighed on sentiment.
Nifty Healthcare and Nifty Auto outperformed while Nifty IT and Nifty Realty fell the sharpest, with Tata Motors PV, Asian Paints, Wipro, HCL Tech and Infosys each losing more than 2%.
Infosys extended its slide to five sessions with a total drop of more than 6%, while Indo-MIM hit the 10% upper circuit at ₹952.75 after profit grew 31.6% to ₹240 crore.
Tempsens Instruments’ ₹650 crore IPO opens on August 20 with a grey market premium of 56%, and Brent crude rose 0.68% to $91.49 on reports of a more offensive Iranian stance.
The 30 share BSE Sensex fell 492.70 points, or 0.63%, to settle at 77,235.46, extending its losing streak to a third straight session. The Nifty 50 fared worse on the streak count, ending lower for a sixth consecutive session as it lost 132.75 points, or 0.55%, to close at 24,154.90.
The broader market was mixed. The Nifty MidCap 100 fell 0.43%, while the Nifty SmallCap settled flat, holding up better than both the benchmarks and the midcap space.
Impact on the stock market
Sectoral gainers: Nifty Healthcare and Nifty Auto outperformed on the day, providing the only real cushion in an otherwise weak session.
Sectoral losers: Nifty IT and Nifty Realty witnessed the sharpest declines. The IT index fell for a third consecutive session and was down nearly 2% on August 18, which explains why Wipro, HCL Tech and Infosys all sat among the top Nifty losers.
| Sector/Index | Performance |
| IT & BPM sector | -1.93% |
| Healthcare sector | 0.21% |
| Oil & Gas sector | 0.20% |
| Real estate sector | -1.42% |
| PSU Bank in India | -1.01% |
Top gainers today
| Company | Share Price (in ₹) | Change % |
| Axis Bank | 1,243.00 | 1.28 |
| Max Healthcare | 1,014.40 | 1.07 |
| M&M | 3,421.50 | 0.92 |
| Grasim | 3,278.70 | 0.87 |
| Power Grid Corp | 268.00 | 0.70 |
Top losers today
| Company | Share Price (in ₹) | Change % |
| TMPV | 322.80 | -2.24 |
| Asian Paints | 2,628.40 | -2.20 |
| Infosys | 1,115.00 | -2.18 |
| Wipro | 178.06 | -2.11 |
| HCL Tech | 1,298.00 | -2.04 |
Market aftermath: Impact on stocks
Tempsens Instruments IPO: A 56% Grey Market Premium Ahead of Launch
The grey market premium for Tempsens Instruments surged to 56% ahead of the issue opening on Thursday, according to platforms tracking grey market activity. Investorgain quoted a premium of ₹168 per share, indicating a potential listing gain of 56%, while IPO Watch quoted 51.33%.
The temperature sensing and heating solutions provider will launch its ₹650 crore initial public offering on August 20, with the issue closing on August 24 and anchor investor bidding scheduled for August 19. The price band has been fixed at ₹285 to ₹300 per share. The company plans to use the proceeds for capital expenditure in its electrical heating solutions and specialised cable solutions businesses, debt repayment and general corporate purposes. A word of caution: grey market premiums signal demand but are unofficial and can swing sharply before listing, so treat the 56% as sentiment rather than a promise.
Infosys: Down 6% in Five Sessions as IT Weakness Deepens
Infosys shares fell for a fifth straight session on Tuesday, declining more than 2% and taking the five session drop to more than 6%. The stock has been tracking the broader weakness in IT, with the sector index down nearly 2% on the day and falling for a third consecutive session.
The pressure has several sources. High geopolitical concerns, rising crude oil prices and elevated US Treasury yields have all weighed on technology stocks, and profit booking after earlier gains has added to the selling. For investors watching Infosys, the question is whether the current slide reflects a temporary reaction to macro nerves or the start of a longer reset. Until oil and yields settle, the sector is likely to stay under pressure.
Indo-MIM: A 10% Upper Circuit on Strong First Quarter Results
Indo-MIM shares hit the 10% upper circuit on August 18, trading at ₹952.75, a day after the company reported strong June quarter results.
The precision components maker recorded a 31.6% year on year jump in net profit to ₹240 crore, from ₹182 crore in the same quarter last year. Consolidated revenue from core operations rose 9.3% to ₹1,219 crore from ₹1,114 crore. Profit growing more than three times as fast as revenue points to improving margins, which is exactly the kind of quality that the market is rewarding while the benchmarks struggle.
Crude Oil: Above $91 as Iran Signals a Harder Line
Crude oil futures traded higher on Tuesday morning after reports that Iran plans to adopt a more offensive stance in the West Asia crisis. October Brent futures were at $91.49, up 0.68%, and October WTI futures were at $84.41, up 0.80%. On the MCX, August crude futures climbed 1.10% to ₹8,152.
The developments were significant. A Reuters report quoting an unnamed senior Iranian official said Iranian entities must be prepared to escalate tensions in the Strait of Hormuz and the wider region, and that Iran would conduct a timely and precise military attack to break the US naval blockade if diplomacy failed. The memorandum of understanding signed between the US and Iran on June 17 to finalise a peace agreement expired on August 17. US President Donald Trump reiterated that the number one goal remains ensuring Iran cannot have a nuclear weapon, while US special envoy Jared Kushner told Fox News that conversations with the Iranian government are more robust than ever, without giving details. Elsewhere in commodities, natural gas rose 0.43% to ₹259 on the MCX, while cottonseed oilcake gained 0.68% to ₹4,310 and castorseed slipped 0.61% to ₹7,038 on the NCDEX.
Conclusion
Tuesday was the week’s toughest session yet. The Sensex fell 493 points, the Nifty logged a sixth straight decline, IT stocks extended their slide and Brent crossed $91 as Iran hardened its position and a key US Iran agreement lapsed. Even so, Indo-MIM’s 10% surge on a 31.6% profit jump and the 56% grey market premium on Tempsens Instruments show that investors are still willing to pay for growth. With the peace memorandum expired and Iran threatening escalation, the Strait of Hormuz remains the single biggest risk on the board. Stay selective, keep some caution in the portfolio and watch the oil price closely.
