India is considering tougher rules for audit firms, including a cap on the number of listed companies they can examine, according to a person with knowledge of the matter, as the government seeks to tighten oversight after a recent spate of governance lapses.

In India, 70% of the about 1,800 companies that trade on the National Stock Exchange are audited by firms affiliated to EY, Deloitte & Touche, KPMG and PWC, according to Delhi-based Prime Database. Current rules stipulate that individual auditors can examine accounts of up to 20 companies, though there is no limit on number of audits for the company.

The Big Four in India operate through a network of local chartered accountants firms. One way for them is to partner as a member of a local firm. They can also allow their brand name to be used by sub-licensee of a member local firm. The ministry hasn’t decided if the cap on audits will be at the group level or on each member firm, the person said.

The government is planning to expand the list of services which can’t be offered by statutory auditors under the Companies Act. Currently, statutory auditors can’t offer nine services, directly or indirectly, including internal audit, investment banking, and actuarial services. There is no restriction on providing services such as taxation or restructuring and valuation.

One option is to tweak the present cap on fees that can be generated through offering non-audit services, the person said. This cap, fixed in 2002, says fees from non-audit work can’t be more than the aggregate statutory audit fees. A spokeswoman for the corporate affairs ministry declined to comment.