Abstract
<jats:p>We provide novel evidence on bureaucratic fragmentation and weak tax administrations as central enablers of low revenue mobilization in low-income countries. In collaboration with the municipal and national tax authorities in Kampala, Uganda, we cross-link previously siloed tax records for 155,000 firms and conduct a large-scale experiment with 60,000 firms. We document pervasive and selective tax evasion: only 14% of verifiably active firms comply with both government tiers. Cross-record linkage almost triples detectable non-compliance while offering increased enforcement efficiency. This coordination dividend is left untapped. Firms exploit the resulting loopholes through partial informality, re-registering under new identities, and strategic late payments. In a cross-authority field experiment, deterrence nudges, including messages signaling inter-authority coordination, fail to offer a light-touch alternative to addressing fragmentation directly. Our findings establish bureaucratic fragmentation as a distinct and costly source of passive waste in tax administration that existing approaches to revenue mobilization rarely address.</jats:p>