Here are a few notable boutique investment banks in Mumbai:

1. Equirus Capital: Equirus Capital is a leading boutique investment bank in India with a strong presence in Mumbai. They offer a range of financial services, including mergers and acquisitions advisory, equity and debt capital markets, private equity, and restructuring services.

2.  Avendus Capital: Avendus Capital is a well-known boutique investment banking firm in Mumbai, offering services in mergers and acquisitions, private equity, structured credit, wealth management, and alternative asset management.

3. Singhi Advisors: Singhi Advisors is a boutique investment banking firm based in Mumbai that specializes in providing mergers and acquisitions advisory and capital raising services for mid-market companies.

4. Edelweiss Financial Services: While Edelweiss is a larger financial services group, they also have a Banking Boutique Firms in Surat arm that operates in Mumbai. They offer advisory services in mergers and acquisitions, restructuring, and capital raising.

5. JM Financial: JM Financial is a diversified financial services group with a boutique investment banking division in Mumbai. They provide services in mergers and acquisitions, equity capital markets, and restructuring.

6. SMC Capitals: SMC Capitals is a boutique investment banking firm that operates in Mumbai, offering services in mergers and acquisitions, private equity, and capital markets.

Please make sure to conduct thorough research and due diligence to confirm the current status and reputation of these firms before engaging with them for any services. It's always advisable to check their websites, client reviews, and recent transactions to assess their expertise and track record in the market.

Top Investment Banks in Delhi

1. ICICI Securities Limited: ICICI Securities is a prominent investment bank and an affiliate to ICICI Bank, one of the largest private sector banks in India. They provide a variety of financial services including equity research, investment banking as well as advisory services.
2. HDFC Bank: HDFC Bank provides investment banking services through its subsidiaries such as HDFC Securities. They provide advisory, brokerage and wealth management to customers.
3. Kotak Investment Banking: As part of Kotak Mahindra Bank, Kotak Investment Banking provides a variety of services such as mergers and acquisitions (M&A) advisory, capital markets for equity as well as debt capital markets as well as corporate financing.
4. Axis Capital Limited: Axis Capital is the investment banking division of Axis Bank, one of the largest private sector banks in India. They provide services like M&A advisory transaction in the capital markets, as well-structured finance.
5. SBI Capital Markets Limited: SBI Capital Markets is the Top investment banks in Delhi arm to the State Bank of India (SBI) the country's largest private sector lender. They offer a range of services, such as consulting on projects as well as mergers and acquisitions and transactions on the capital markets.
6. Edelweiss Financial Services Limited: Edelweiss is a diverse financial services business which provides investment banking services, which include M&A advisory capital raising, as well as wealth management.
7. Yes Securities (India) Limited: Yes, Securities is the branch of the Top Investment Banking Boutique Firms in Delhi business from Yes Bank, providing various financial services such as corporate finance, investment banking as well as wealth management.

Be aware that the positions and importance of these banks' investment banking operations could alter in time. It is recommended to conduct a thorough research and due diligence prior to selecting a financial service provider. In addition, the offerings offered by investment banks Delhi can differ, which is why it's important to evaluate your needs for investment and goals to determine the best partner.