This is an interesting legal question with a historical explanation:
1. Historical Background: The Indian Partnership Act, 1932 is the governing law for partnership firms. Interestingly, the cap on the maximum number of partners was originally prescribed under Section 11 of the Companies Act, 1956 (now Section 464 of the Companies Act, 2013) — NOT in the Partnership Act itself.
2. Why the Companies Act? The rationale is rooted in company law policy: Any association of persons formed to carry on business for profit with more than the prescribed maximum number of members, WITHOUT being registered as a company, was deemed illegal under the Companies Act. This was to prevent large unregistered associations from operating without the transparency and regulatory framework of company registration. - The Companies Act set the ceiling at 20 partners for non-banking businesses and 10 for banking businesses under the old law - The intent was: if you want more than that many partners, incorporate a company (or LLP)
3. Current Position Under Companies Act, 2013: Section 464 empowers the Central Government to prescribe the maximum number of persons/partners. Rule 10 of Companies (Miscellaneous) Rules, 2014 prescribes the maximum as 50 partners for any partnership firm.
4. LLP as Alternative: The Limited Liability Partnership Act, 2008 provides for LLPs with NO upper limit on partners — this effectively removed the practical constraint for large professional firms.
5. The Partnership Act's Silence: The Partnership Act, 1932 does not prescribe a maximum number because it predates the company law policy concern — that limit was overlaid by company legislation as a regulatory measure.