abstract: 'Exploiting heterogeneous variations in labour cost increases due to Japan''s 2003 social insurance premium reform as a natural experiment, we estimate the impacts of the increased social insurance premiums on employment, working hours and payroll costs. Using the difference-in-differences method with establishment fixed effects, we find that firms reduce the number of employees and increase average annual earnings from longer working hours in response to an exogenous increase in labour costs without productivity gains. Firms manage to pay for this increase in the average wage paid to the remaining workers by reducing the number of employees to keep total payroll costs unchanged. In contrast, since social insurance premiums are shared equally between employees and employers, firms pay the remaining half premiums that they are imposed with. Sub-sample analyses show that firms adhering to a labour hoarding policy did fire many workers taking advantage of the 2003 reform. This may indicate that the reform provided a good excuse to cut employment in firms that had been forced to comply with a labour hoarding policy even in an over-employment situation, which is more likely in sectors and countries where dismissals are rigorously regulated.' affiliation: 'Kodama, N (Corresponding Author), Hitotsubashi Univ, Grad Sch Econ, 2-1 Naka, Kunitachi, Tokyo 1868601, Japan. Kodama, N (Corresponding Author), METI, Res Inst Econ Trade \& Ind, Chiyoda Ku, 11th Floor,1-3-1 Kasumigaseki, Tokyo 1008901, Japan. Kodama, Naomi; Yokoyama, Izumi, Hitotsubashi Univ, Grad Sch Econ, 2-1 Naka, Kunitachi, Tokyo 1868601, Japan. Kodama, Naomi, METI, Res Inst Econ Trade \& Ind, Chiyoda Ku, 11th Floor,1-3-1 Kasumigaseki, Tokyo 1008901, Japan.' author: Kodama, Naomi and Yokoyama, Izumi author-email: 'kodama.naomi@r.hit-u.ac.jp izumi.yokoyama@r.hit-u.ac.jp' author_list: - family: Kodama given: Naomi - family: Yokoyama given: Izumi da: '2023-09-28' doi: 10.1111/obes.12226 eissn: 1468-0084 files: [] issn: 0305-9049 journal: OXFORD BULLETIN OF ECONOMICS AND STATISTICS keywords-plus: 'PAYROLL TAXES; WAGE; INSTITUTIONS; BONUS; EXPERIENCE; INEQUALITY; EMPLOYMENT; INCOME; BEARS; PAY' language: English month: OCT number: '5' number-of-cited-references: '45' orcid-numbers: Yokoyama, Izumi/0000-0003-4661-2670 pages: 992-1019 papis_id: 9d5cbbaee5e129c3b2a3ee8d5acb0a19 ref: Kodama2018labourmarket researcherid-numbers: 'Kodama, Naomi/HNB-9949-2023 Yokoyama, Izumi/T-8665-2017' times-cited: '2' title: 'The Labour Market Effects of Increases in Social Insurance Premium: Evidence from Japan' type: Article unique-id: WOS:000443403200007 usage-count-last-180-days: '2' usage-count-since-2013: '25' volume: '80' web-of-science-categories: 'Economics; Social Sciences, Mathematical Methods; Statistics \& Probability' year: '2018'