LONDON -- The FTSE 100 (INDEX: ^FTSE) is bouncing back a bit today, up 0.6% to 5,877 points and reversing yesterday's decline. The index has been slowly pushing upwards in recent weeks, but sentiment seems to keep holding it back from the utterly unimportant 5,900 level.

But even if the FTSE is up a bit, some individual constituents of the various indexes are not having such a good day.

Morgan Sindall (LSE: MGNS.L)
Shares in construction firm Morgan Sindall slumped today, dropping 5.7% to 623 pence after the firm released a profit warning and told us that chief executive Paul Smith has resigned. We were told that, due to continuing difficulties in the U.K. construction business, this year's trading is now going to be "slightly below" current expectations.

The latest consensus suggested a full-year profit of 43 million pounds, and that is certain to be downgraded now. But we're still going to be left with the shares on a forward price-to-earnings ratio of less than nine. A dividend of 42 pence per share was also forecast, which amounts to 6.7%, so there's plenty of room for a cut there, too, while still leaving an attractive payout.

DS Smith (LSE: SMDS.L)
Packaging supplier DS Smith saw its shares lose 4.2% to 206 pence despite a first-half trading update confirming that things are going as expected. Margins are expected to be within the previously published target of 7% to 9%, and European trading has been strong, although trading in the U.K. has apparently been "held back by its high exposure to the paper cycle."

For the full year, the firm is expecting "substantial year-on-year EPS growth."

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Premier Oil (LSE: PMO.L)
Premier Oil dropped 1.6% to 354.5 pence after its Spaniards East well failed to produce the black stuff and was plugged and abandoned. The exploratory well, which was drilled to a depth of more than 10,000 feet, found 75 feet of Jurassic sands, but they turned out to be waterlogged.

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