Non-mandatory business surveys generally suffer from low response rates and potential non-response bias. Achieving a response is most problematic in small- and medium-sized enterprises because of their scarce human resources. The problem becomes exacerbated in fast-growing companies – ‘gazelles’. The paper addresses the effectiveness of data collection efforts to achieve a response among the top Slovenian gazelles in 2008. We analyse the impact on response rates and data quality. Finally, we look for evidence of non-response bias.