This paper presents a detailed account of the rich set of macroprudential measures (MPPs) implemented in Bulgaria, Croatia, Romania, and Serbia during their synchronized boom and bust cycles in 2002-12, and assesses their effectiveness in managing credit growth. Only strong MPPs helped contain domestic credit growth during the boom years, but circumvention via direct external borrowing offset their effectiveness to a large extent. MPPs taken during the bust had no discernible impact. The paper concludes that (i) proper calibration of MPPs is of the essence; (ii) only strong, broad-based MPPs can contain credit booms; (iii) econometric studies of macroprudential policy effectiveness should focus on concrete policy measures rather than on instruments use; and (iv) in so doing should allow for possible non-linear and state-contingent effects.