Sensex vs KOSPI: Does India’s sector diversity offer an edge over South Korea’s chip-heavy index?

South Korea’s KOSPI has witnessed a sharp reversal in just a month. The index plunged from 8,476 points on 30 June to 5,593 points by 31 July, a fall of about 34%, before recovering much of those losses and narrowing the decline significantly over the last few trading sessions.

The KOSPI gained nearly 116% in H1 2026, briefly making South Korea the world's sixth-largest stock market, touching an all-time high of 9,385 points on 19 June. This happened after a large share of global capital was pulled away from markets like India toward artificial intelligence- and semiconductor-driven markets such as Taiwan and South Korea.

The dramatic crash and rebound cycle has renewed attention on the index's heavy dependence on a handful of semiconductor companies, particularly Samsung Electronics and SK Hynix.

The episode raises an important question for investors: Does India's Sensex, with its wider spread across banking, IT, energy, consumer and industrial sectors, offer a more diversified market? Here's what experts say and what their advice means for investors seeking returns in an increasingly volatile environment shaped by AI frenzy and geopolitical tensions in West Asia.

Why were investors spooked away from the KOSPI earlier?

The earlier correction in the KOSPI is better viewed as a repricing of expectations rather than the end of the AI story, said Harendra Zatakia, a Sebi-registered investment advisor and the Founder of Wealth Aligned Financial Advisory.

South Korea's KOSPI advanced nearly 4% today, extending its recent outperformance and effectively breaking free from bear-market territory. This proves that investors are still as enthusiastic about the AI game, but it also comes with risks, as we recently witnessed.

“Samsung Electronics and SK Hynix together account for more than half of the KOSPI's market capitalisation, making the index highly sensitive to sentiment around semiconductors and AI,” he noted.

Speaking of the recent bouts of volatility, he said that after a strong rally, valuations had begun reflecting very optimistic expectations around AI-driven earnings. Concerns over the pace of AI infrastructure spending, memory-chip demand, and profit-booking after a sharp rally triggered a correction, which was amplified by the index's high concentration in just two companies, he added.

“Investors should remember that concentration in a single sector or theme can significantly increase portfolio volatility,” he added.

Is India more diversified than the KOSPI?

According to Zatakia, India has not avoided concentration risk, but the nature of that risk is quite different. Unlike the KOSPI, which is heavily dependent on a handful of semiconductor companies, India's stock indices have a broader sectoral representation, he added. Here's what it looks like:

• Financial Services account for about 35% of the index
• Oil & Gas accounts for about 10% of the index
• IT contributes about 9%
• Automobiles make up around 7% of the index
• FMCG stands at 6%

“Both the Nifty 50 and Sensex are market-cap weighted indices, meaning larger companies naturally have a greater influence on index performance. Therefore, concentration is an inherent feature of index construction,” the expert noted.

Sharad Kohli, an economist and market expert, also mirrored Zatakia's views. He highlighted that India is not relying on just one industry to drive the market, unlike South Korea's KOSPI.

“Domestic consumption, financial services, infrastructure, manufacturing and technology all contribute. That naturally makes the market a little more balanced,” the expert said.

Should domestic investors stay focused only on India?

Kohli said that the lesson from KOSPI's recent dramatic swing is not to avoid overseas markets; the lesson is not to chase whichever market is making headlines. In other words, he advises people to avoid the “herd mentality”.

“India can remain the core portfolio, while global investments should be about diversification, not excitement,” he said.

Hence, the key takeaway from their views is that holding more of an index does not automatically eliminate concentration risk. Investors are advised to look beyond the number of constituents and understand what actually drives the index's earnings and performance.