The S&P/ASX 200 Index (ASX: XJO) was on course to record a small gain last week until a pullback on Friday. This led to the benchmark index finishing the week 1.8 points lower at 7,392.6 points. A number of ASX 200 shares performed particularly poorly and weighed heavily on the index. Here’s why these were the worst performers over the five days: Crown Resorts Ltd The Crown share price was the worst performer on the ASX 200 last week with a 14.1% decline. This casino and resort operator’s shares have come under significant pressure since Star Entertainment Group Ltd (ASX: SGR) announced that it was ending merger talks. Star advised that while it remains interested in a potential merger, there is just too much uncertainty at present. It notes that there are concerns that Crown could lose its Melbourne licence.