Tax Enforcement Spillovers - Evidence from Business Tax Audits in South Africa

Taxpayer audits are key instruments to combat tax evasion. Whether they deter tax non-compliance beyond audited taxpayers is largely unclear, however. Drawing on rich tax administrative data for South Africa, we show that business tax audits enhance the tax reporting compliance of unaudited firms in the same local network as the targeted business. On average, firms’ reported tax liability increases by around 1.5% when a business in close proximity (located within a 100m radius) undergoes an audit. This estimate translates into sizable aggregate revenue gains, as audited firms are linked to numerous neighbors. Additional analyses show that audit spillovers emerge across a larger spatial scale within industry and tax preparer networks. Our findings carry important implications for the design of tax enforcement policies.