I hardly call less than 5% below all time high as 'hammered'.
But when the yield is as low as it is now with MMP, PAA, SXL and a few others you have to expect it. It is priced for perfection and continuation of high growth rate. Any little bump will send the price down. After all, with yield at 4%, it can hardly go much higher other than by the same percentage as distribution increases.
The stock fell more than 2% on substantially higher than normal volume and this occurred on a decent day on Wall Street. Moreover, none of its sisters in the industry suffered anywhere near what happened today to MMP. It got hammered. Just the facts. Where it sits in relation to its all time high has no relevance to my observation. I own the stock but I don't cheerlead.