If you check/compare the Yahoo Historical Prices you will see that KMP always dips after the x-date; then, dips further in the spring & summer, when the need for gas subsides. Comparing past with present, can sometime enlighten the future, depending on what’s going on with in the company. When approaching another earning cycle; and, the winter months, KMP always starts moving up. No need for all the worry.
ex dividend selling ... very normal. If you look back on the chart, you'll see selloff's every quarter at this time. My guess is it should have support here in the 80's. The yeild going forward is 5.85% @ $85. The El Paso acquisition boost to payouts will take effect later in the year. With the Fed saying that they will keep rates at zero for the next two years, I don't think KMP has anything to worry about.