SAST stands for Substantial Acquisition of Shares and Takeovers - SEBI's regulations governing what happens when someone buys a large stake in a listed company (the SEBI SAST Regulations, 2011, commonly called India's "Takeover Code"). The idea: if you quietly buy up shares and cross certain thresholds, you must disclose it; and if you cross 25% you must make an open offer - a public bid to buy more shares from all other shareholders at a fair price - protecting minority shareholders when control changes hands. VIGIL tracks the Regulation 29 disclosures: whenever someone crosses 5% ownership, or their holding changes by 2% or more after that, they must file within 2 working days.
Open the live VIGIL Takeover (SAST) view for the full, filterable disclosure feed.
The key thresholds
| Threshold | What happens | Regulation |
|---|---|---|
| 5% shareholding | Must disclose to the exchange within 2 working days | Reg 29(1) |
| Every 2% change (after 5%) | Must disclose again each time holding changes by 2% or more | Reg 29(2) |
| 25% shareholding | Mandatory open offer triggered - must offer to buy 26% more from all shareholders | Reg 3(1) |
| 25-75% + buying over 5%/year | Holding 25-75% and buying more than 5% in a financial year triggers an open offer | Reg 3(2) |
| Acquiring control | Gaining control (even without crossing 25%) triggers an open offer | Reg 4 |
| 75% cap | No one may exceed 75% (minimum 25% must remain with the public) | SEBI LODR |
Open offer size: mandatory offers (Reg 3/4/5) require a bid for at least 26% of total shares; voluntary offers (Reg 6) at least 10%. The offer price has a floor based on historical trading prices and the price paid to the seller. Source: SEBI Master Circular for SAST (Feb 2023).
Regulation 29(1) vs 29(2)
Reg 29(1) - Initial 5% disclosure: a one-time event, filed when someone (with persons acting in concert) first crosses 5%. Reg 29(2) - Continual 2% change disclosure: an ongoing obligation - once past 5%, every 2%+ move (buying or selling) triggers a fresh filing, creating a trail investors can follow (e.g. 7% to 9% is a 29(2) filing; selling 9% down to 6% is another). In VIGIL's data about 87% of filings are Reg 29(2) and 13% are Reg 29(1). Source: SEBI Reg 29 Disclosure Formats (Oct 2011).
Who has to file?
Unlike insider trading (which covers only company insiders), SAST applies to anyone crossing the thresholds:
- Promoters - controlling shareholders / founders; about 70% of SAST filings are by promoters (marked "Y" in the Promoter column).
- Non-Promoters - institutional investors, PE/VC funds, mutual funds, FPIs, or any external party building a stake. Often the most interesting filings - someone outside the company is accumulating shares, possibly as a precursor to a takeover or activist campaign.
- Persons Acting in Concert (PAC) - multiple entities working together are treated as one group, with holdings combined for threshold calculations. Promoter-group members (family trusts, holding companies) are deemed to be acting in concert by default.
How shares are acquired
| Mode | What it means | Signal |
|---|---|---|
| Open Market | Buying / selling through the regular stock exchange | Deliberate stake building - the acquirer is actively buying |
| Inter-se Transfer | Transfer between promoter-group members (e.g. founder to family trust) | Usually internal restructuring, not a change in control |
| Preferential Allotment | Company issues new shares directly to the acquirer at a negotiated price | Often part of a fundraising or strategic investment |
| Rights Issue | New shares offered to existing holders pro-rata | If only the promoter subscribes, their percentage rises |
| Others | Off-market block deals, gift, inheritance, encumbrance invocation, etc. | Context-dependent - succession to forced sale |
In VIGIL's data, Open Market is about 53% of filings, followed by Others (33%) and Inter-se Transfer (9%).
How SAST differs from Insider Trading (PIT)
| SAST (Takeover Code) | PIT (Insider Trading) | |
|---|---|---|
| Who | Anyone crossing a threshold - promoters, PE firms, acquirers, any investor | Company insiders only - promoters, directors, KMPs, designated employees, relatives |
| What | Only large acquisitions (5%+ threshold, 2%+ changes) | ALL insider trades, even small ones (above Rs 10 lakh/quarter) |
| Purpose | Takeover transparency - a big stake is being built and minority holders deserve to know | Information fairness - are insiders trading on non-public information? |
| Volume | ~9,700 records in 2 years (fewer, bigger deals) | ~31,000 records in 2 years (many small trades) |
| Red flag | Hostile takeovers, promoter stake changes, PE exits, control shifts | Unusual insider selling before bad news, bulk buying before good news |
There is overlap - a promoter buying a large block can appear in both - but the angle differs. See the Insider Trading page for the PIT side.
Real-world takeover examples
SAST disclosures have been at the center of some of India's most high-profile corporate battles:
L&T vs Mindtree - India's first IT hostile takeover (2019)
Mindtree co-founder V.G. Siddhartha sold his 20.4% stake to L&T in March 2019; L&T then bought more on the open market, crossing 25% and triggering a mandatory open offer for 31% more. The founders fought back but found no white knight; L&T ended with ~60% and the co-founders resigned. In 2022 Mindtree merged with L&T Infotech to form LTIMindtree. The Reg 29 disclosures showing L&T going 0% to 28.9% within days were the clear early warning.
Adani Group vs NDTV - the indirect acquisition (2022)
In 2009 NDTV's founders borrowed Rs 403 crore by pledging their 29% stake and issuing convertible warrants. In August 2022 Adani quietly acquired the entity holding those warrants, gaining the right to convert them into a 29.18% stake - crossing 25% and triggering a mandatory open offer. After the offer, the Roy founders sold their remaining 27% to Adani (~65% total). This showed how indirect acquisitions (buying a holding company with conversion rights) trigger SAST obligations under Regulation 5.
Burman Family (Dabur) vs Religare - the 16-month board battle (2023-2025)
The Burman family built a Religare stake via open-market purchases, crossing 25% in September 2023 and triggering a mandatory open offer at Rs 235/share. Management fiercely opposed it - delaying applications, questioning the offer price - until SEBI intervened and RBI approved the deal in December 2024. The Reg 29(2) continual disclosures showed steady accumulation, each 2% filing signalling intent.
Invesco vs Zee Entertainment - shareholder activism (2021)
Invesco, holding 17.88% of Zee, demanded removal of the MD/CEO and six new directors - a fight for control via board changes rather than a straight acquisition. Zee argued that gaining board control would amount to acquiring "control" under SAST and require an open offer. The case reached the Bombay High Court; Invesco withdrew after Zee announced a (later-collapsed) Sony merger. It raised the question: does replacing a majority of the board amount to acquiring control under SAST?
Bain Capital vs Manappuram Finance - PE-driven acquisition (2025)
In March 2025 Bain Capital agreed to acquire an 18% stake in Manappuram Finance (a leading gold-loan NBFC) for approximately USD 508 million, with plans to raise to 40%+ via a mandatory open offer - a major private-equity acquisition of a listed Indian NBFC requiring both SEBI SAST compliance and RBI approval.
Why SAST disclosures matter for investors
- Stake building = something big may be coming. Repeated Reg 29(2) filings showing rising ownership often precede an open offer, takeover bid, or strategic investment. In every major takeover above, the Reg 29 trail was visible first.
- Promoter selling = potential control shift. Significant promoter reduction (via open-market sales, not inter-se transfers) can signal lost interest, debt distress, or an impending exit.
- Non-promoter accumulation = activist or acquirer. An external PE firm, hedge fund, or strategic buyer filing Reg 29 means they are building a meaningful position - exactly how the Burman-Religare saga began.
- Open offer = guaranteed exit at a set price. When triggered, all shareholders can sell at the SEBI-regulated offer price (which has a floor) - a concrete benefit of the Takeover Code for minority investors.
Coverage
Data from January 2024 onwards, 1,370+ unique companies (all NSE-listed equities), 9,700+ disclosures and growing, synced from NSE multiple times daily. Each record includes the acquirer name, company, shares acquired/sold, percentage holding before and after, acquisition mode, and the original filing attachment. Source: NSE's SAST Regulation 29 filing system.
References and key terms
SEBI: SAST Regulations 2011 (consolidated, Nov 2024) · Master Circular for SAST (Feb 2023). NSE: Reg 29 (Promoters) · Reg 29 (Non-Promoters).
- Open Offer - a public bid to buy a specified percentage of shares from all holders at a regulated price; mandatory when crossing 25% or acquiring control.
- PAC (Persons Acting in Concert) - multiple cooperating entities whose holdings are aggregated; promoter-group members are deemed PAC by default.
- Creeping Acquisition - gradually increasing a stake (up to 4.99%/year is allowed without an open offer for holders between 25-75%).
- Indirect Acquisition - acquiring control by buying the parent / holding company (as Adani did to reach NDTV).
- Reg 29(3) - holders of 25%+ must make an annual disclosure as of March 31 each year, even with no change.
Open the live VIGIL Takeover (SAST) view on TIGZIG, or see the related Insider Trading page and all VIGIL data sources.