In this article, Andrew Bowen QC looks at Share Purchase Agreements and Penalties in the context of Cavendish Square Holdings BV v Makdessi. This case usefully summarises the modern law on penalties and emphasises the courts reluctance to interfere with contractual provisions which have been properly negotiated. This article was first published in Greens Business Law Bulletin, Issue 125 (published August 2013) and is reproduced here with the kind permission of W. Green, The Law Publishers.