• Mainboard IPOs are for large, established companies seeking to raise substantial capital by listing on NSE and BSE with a typical issue size of a minimum of 200Crs. Mainboard IPO attract large institutional investors including mutual funds, AIFs, and a very wide base of retail investors. A Mainboard IPO requires approval of stock exchanges as well as SEBI and the overall process takes between 10-12 months.
• SME IPOs are designed for small and medium companies to raise funds by listing on SME platforms like NSE Emerge or BSE SME with a typical issue size of INR 25-100Crs. SME IPOs attract investors like family offices, AIFs, Ultra HNIs and a limited set of retail investors. SME IPO requires approval from respective stock exchange only and the overall process takes between 6-8 months. 

Two possible routes have been given by SEBI for a company to become an IPO issuer.
1. Profitability Route
a) Net tangible assets of at least Rs 3 crores in each of the three preceding years, provided for fresh issue (not OFS) of the Rs 3 crores of net tangible assets, if more than 50% should net tangible assets is cash or cash equivalent then issuer has to utilized or make firm commitments to utilize such excess cash and cash equivalent in its business or project
b)Average operating profit of at least fifteen crore rupee during the preceding three years, with
operating profit in each of these preceding three years
c)Net worth of at least one crore rupees in each of the preceding three full years
d)In case of a name change, 50% of the revenue generated in the preceding year should be from the business carried under the new name
2. QIB Route
a)IPO only if the issue is made through the book-building process
b) Issuer undertakes to allot at least 75% of the net offer to QIB
c)Refund the full subscription money if it fails to fulfill the above 2 conditions

BSE SME Eligibility Criteria:
a)Post-issue paid-up capital must be at most INR 25 crore
b)Net worth of at least INR 1 crore for the preceding two full financial years
c)Net tangible assets of at least INR 3 crore in the last preceding full financial year
d)Company should have a positive operating profit (EBITDA) in at least two out of the three preceding financial years, provided that there is an operating profit from operations for one full financial year preceding the application date
e)Leverage ratio should not exceed 3:1, though there is a relaxation for finance companies
f)Track record of at least 3 years, where compnay has taken over a PF/ LLP/ Proprietorship concern, then track record together shall be 3 years (company should be operational & have audited financials of at least 1 full FY)
If not, a project for which the IPO is being proposed should be appraised and funded by NABARD, SIDBI, Banks (other than co-operative banks) or Financial Institutions. 
NSE SME Eligibility Criteria:
a)Post-issue paid-up capital must be at most INR 25 crore
b) The company should have a positive net worth
c) Company should have a positive operating profit (EBITDA) in at least two out of the three preceding financial years, provided that there is an operating profit from operations for one full financial year preceding the application date
d)Track record of at least 3 years of either : 
i)Applicant seeking listing or
ii)Promoters/promoting company, incorporated in or outside India or
iii)Proprietary/ partnership firm converted into a company seeking listing

• SME – 6 -8 months
• Mainboard – 10-12 months

• Fixed Price Issue sets a specific price for the shares before the IPO opens. Investors know the exact price they will pay per share, and shares are allocated at this fixed price.
• Book Building involves setting a price range for the shares. Investors submit bids within this range, and the final price is determined based on demand.

• Price Discovery: Helps determine a fair market price for shares based on investor demand, leading to better price accuracy
• Market Feedback: Provides insights into investor sentiment and market conditions before finalizing the price
• Flexibility: Allows for price adjustments within the bid range, optimizing capital raised.
• Enhanced Allocation: Helps in efficient allocation of shares to interested and qualified investors.

For IPO, a company should assess its internal readiness by seeking assistance from a financial advisor. A merchant banker and a legal advisor are then appointed and the company then undergoes a complete due diligence process to prepare a Draft Red Herring Prospectus (DRHP). After preparing the DRHP, the company files it with the stock exchanges and SEBI. Post the filing of the DRHP, the company replies to all queries from the stock exchanges and SEBI. Upon addressing these queries, the company receives approval from the stock exchanges and SEBI to file the Red Herring Prospectus and open the issue. Once the issue is fully subscribed and closed, the company files the Prospectus with the Registrar of Companies and SEBI

• Draft Red Herring Prospectus (DRHP) – A preliminary prospectus filed with SEBI, containing details about the business, financials, and risks.
• Final Red Herring Prospectus (RHP): The final version of the DRHP, updated with pricing information.
• Restated Financial Statements: Financial records for at least three years, prepared according to Ind AS.
• Due Diligence Certificate: Issued by the merchant bankers and legal advisors, confirming thorough checks of the company’s disclosures.
• Corporate Governance Reports: Documentation proving adherence to corporate governance norms.
• Material Contracts and Agreements: Copies of significant contracts and agreements impacting the business and its operations

• Mainboard IPO – 8-10% of the issue size
• SME IPO – 12-15% of the issue size
Majority of the above fees ia payable only on success of the IPO.