For equity transactions pertaining to minority stake investments in India, there exist various regulatory conditions that are required for private equity firms to invest in companies situated in India:

1. Companies Act, 2013 – This act lays down the procedure for mergers and acquisitions including the regulation of process of issuance and transfer of securities. It also sets out corporate governance framework for the Indian companies. It also prohibits the foreign company to leverage their assets to raise investments. It also bars the Indian companies to provide financial assistance to any person for the purchase of their shares. 
2. Foreign Exchange Management Act, 1999 – As the increase of liberalisation in the Indian economy, foreign investments in equity instruments are dealt by the Foreign Exchange Management Act and the rules and regulations thereunder. All the regulations that are framed by the government from time to time are also covered under the purview of this act. There are two routes through which a foreign investor may invest, i.e. either directly or as a foreign portfolio investor registered with the SEBI. All the investments that are less than 10% in the shares of a listed company by a SEBI registered investor is treated as a foreign portfolio investment while a foreign investment in an unlisted company or in 10% or more of shares of a listed company is known as FDI. 
3. RBI – Investments in certain sectors such as the financial, telecom and insurance sectors are subject to the incremental restrictions and the conditions imposed by the relevant sectoral sectors. The RBI monitors the management and ownership of banks and NBFCs in India and prior approval of RBI is required for change in shareholding or management linked to specific thresholds. 
4. Taxation Regulations – Transfer of securities of an Indian company to a foreign company through FPI or FDI generally attracts the capital gains tax in India in the hands of the seller. On the part of the purchaser, there is an obligation to withhold taxes from the consideration payable to non-resident sellers. 
5. Antitrust Issues – Any M&A transaction will require the notification to and approval of the CCI. If the assets or turnover of the parties to the transaction exceed a certain specified threshold. There are certain combinations of companies such as Jio Chat and WhatsApp for instance that are likely to cause an Appreciable Adverse Effect on the Competition (AAEC) in India are prohibited by the CCI. 

Companies and institutional investors interested in acquiring minority stakes in Indian companies need to ensure compliance with above-mentioned regulations, as applicable to specific transactions.