Foreign institutions were net sellers on Thursday, 8 October, to the tune of ₹12,943.60 crore, one of the largest daily figures this year. On Friday the Nifty rose 1.30% (today's post-market report). That got me asking a plain question of my own records: after a day of FII selling, how often does the Nifty actually fall?
The short answer from 53 sessions: the Nifty fell the next day on 20 of 32 days after FII selling, and on 11 of 21 days after FII buying. That is a difference, but a small one, inside a period when the Nifty fell on most days anyway. Everything below is a count of past days, not a forecast.
The question and the data
The question. When foreign institutional investors (FIIs) are net sellers in the cash market on one day, does the Nifty tend to open lower, or close lower, on the next trading day? And does it matter how big the sale was, or what domestic institutions (DIIs) did?
The data. My bot's market log has recorded NSE's provisional FII and DII cash-market figures each evening since 17 July 2026. There are 54 recorded days, from 17 July to 1 October 2026. The same log has the Nifty's daily open, close and previous close. Pairing each flow day with the next trading session gives 53 pairs: 1 October has no next day in the log yet.
Two things to keep in mind:
- 53 pairs is a small sample. One day changing sides moves a group's share by two to five percentage points.
- The period leaned down. The Nifty closed at 24,342.35 on 17 July and 22,421.95 on 1 October, a fall of 1,920.40 points (7.89%). FIIs sold on 33 of the 54 days and DIIs bought on 49.
If you want a refresher on what these figures are and how NSE reports them, the FII and DII section of the post-market reports shows a typical day.
How I counted
For each flow day I took:
- FII side: net seller (negative figure) or net buyer.
- Next-day close: the next session's close minus its previous close. Up or down.
- Next-day gap: the next session's open minus the previous close. No session in the sample opened exactly flat.
- Next-day body: whether the next session closed above or below its own open.
I also grouped the selling days by size (₹5,000 crore or more, and under), and counted what DIIs did on the same days. All of these are counts. I've given average point moves where they help, but averages over 6 or 21 days are pulled around by single days, so read them loosely.
Results: next-day close
| After a day when FIIs were... | Days | Nifty up next day | Nifty down next day | Average next-day move |
|---|---|---|---|---|
| Net sellers | 32 | 12 (37.5%) | 20 (62.5%) | −49.2 pts |
| Net buyers | 21 | 10 (47.6%) | 11 (52.4%) | −16.5 pts |
| All days | 53 | 22 (41.5%) | 31 (58.5%) |
After selling days the Nifty fell 62.5% of the time. After buying days it fell 52.4% of the time. Across the whole sample it fell 58.5% of the time.
So the useful comparison is not "62.5% versus a coin toss", it's "62.5% versus 58.5%". Most of the downward lean after selling days is simply the market these 53 days came from. Even after FII buying days, the next day was more often down than up.
Results: the opening gap and the rest of the day
The opening gap is where you'd expect a flow figure to show up first, because it's published the evening before.
| After FIIs were... | Gap up | Gap down | Average gap |
|---|---|---|---|
| Net sellers (32) | 14 | 18 (56%) | −23.3 pts |
| Net buyers (21) | 12 (57%) | 9 | +20.2 pts |
This is the clearest split in the data: the next open leaned the same way as the previous day's FII figure, 56% of the time after selling and 57% after buying. It's still close to a coin toss in each group.
What happened after the open was less tidy:
| After FIIs were... | Closed above its open | Closed below its open |
|---|---|---|
| Net sellers (32) | 14 | 18 |
| Net buyers (21) | 7 | 14 |
After buying days, the next session closed below its own open on 14 of 21 days. Put the two tables together and the buying-day pattern is: open a little higher, then drift lower during the day. I don't have a reason for that and won't invent one. It's 21 days in a falling market. If you're curious about how often an opening gap gets taken back, I counted that separately in how often the Nifty fills its opening gap.
Does the size of the sale matter?
| FII net selling | Days | Next day up | Next day down | Average next-day move |
|---|---|---|---|---|
| ₹5,000 crore or more | 6 | 1 | 5 | −73.8 pts |
| Under ₹5,000 crore | 26 | 11 | 15 | −43.5 pts |
Five of the six large selling days were followed by a lower close. That looks striking until you count the days: six. Three of them came in the last week of September (29 and 30 September were the two largest sales in the sample, ₹9,980 crore and ₹10,148 crore), when the market was falling day after day. They aren't six independent events.
The most recent large sale sits just outside the sample and went the other way. FIIs sold ₹12,943.60 crore on 8 October, more than any day in the log, and the Nifty rose 1.30% on 9 October. The day before, FIIs sold ₹6,121.40 crore on 7 October and the Nifty fell 1.64% on 8 October. One each way.
The DII side
Looking at FII figures alone leaves out the other half of the table. On 31 of the 32 days FIIs sold, DIIs bought. On 24 of those 31 days, DII buying was larger than FII selling. Over the 53 days, FIIs sold a net ₹53,153 crore and DIIs bought a net ₹1,49,342 crore.
So I also counted days by the combined institutional figure (FII plus DII):
| Combined FII + DII | Days | Same day: Nifty down | Next day up | Next day down |
|---|---|---|---|---|
| Net sellers | 8 | 7 | 2 | 6 |
| Net buyers | 45 | 20 | 25 |
Combined institutional selling happened on only 8 days. The Nifty fell on 7 of those same days, which is what you'd expect: these figures describe the day that's just ended. The next day it fell 6 times out of 8. Again, 8 days.
The same-day link is not much stronger
One more check, because it puts the next-day numbers in context. If FII figures are strongly tied to the Nifty at all, it should show up on the same day, since the flows and the price move happen together.
On the 32 FII selling days, the Nifty itself fell on 19 and rose on 13, with an average move of −45.7 points. On the 21 buying days the average same-day move was +0.2 points. Selling and a falling index went together more often than not, but there were plenty of days with heavy FII selling and a higher close, because DII buying more than made up for it.
Limitations
- Small sample. 53 pairs, split into groups of 6 to 32 days.
- One kind of market. The Nifty fell 7.89% over the period. I can't say what these counts look like in a rising market until the log covers one.
- Provisional figures. The log records NSE's provisional evening figures. Final figures can differ slightly.
- Cash market only. FIIs also trade index futures and options, and those positions aren't in the cash figure.
- No control for news. Results, crude oil, policy announcements and global markets move the Nifty far more than one evening's flow figure. On 9 October, for example, TCS's results and lower crude prices were the reported drivers.
What I take from it
- The FII figure describes yesterday. It's a summary of a session that has already happened, and in this sample its link to the next day's close is weak once you allow for how the market was trending.
- The opening gap leaned with the flows slightly. 56% and 57%. That's a description of 53 past days, not something I'd build a rule on. It fits with what I found about the pre-market read: the overnight picture says something about the open and much less about the close.
- Read FII and DII together. A large FII sale on a day DIIs bought even more is a different day from one where both sold. The combined figure was negative on only 8 of 53 days.
I'll rerun this when the log reaches 100 flow days, and I'll split it by whether the Nifty was above or below where it started that month. If you want the daily figures as they come in, they're in each evening's post-market report, and the overnight context, including GIFT Nifty, is in the pre-market report.
Sources
- FII and DII provisional cash-market figures, 17 July to 1 October 2026: NSE, as recorded in my own market log each evening
- Nifty 50 daily open, close and previous close: my own market log, from Zerodha Kite market data
- 7 and 8 October FII figures: 5paisa FII/DII data
- How NSE reports the figures: NSE FII/DII trading activity
- 8 and 9 October Nifty moves: Zerodha Kite market data, as published in the 8 October and 9 October post-market reports
This post shares my own analysis of past data for information only. It is not investment advice or a recommendation to buy or sell any security. I am not registered with SEBI as an investment adviser or research analyst.