LONDON -- The FTSE 100 (INDEX: ^FTSE) is continuing its slump today, falling a further 102 points, or 1.6%, to 6,298 by 8:15 a.m. EDT -- those who care about such things will now be fretting about the index failing to hold onto the 6,300 level.

The miners are slipping again as fears of a Chinese slowdown take a further grip, and the gloom has been worsened by the Bank of Japan's decision not to take any further stimulus steps.

But which companies are leading the fall? Here are three from the various indexes that are sliding and look set to lag the market today.

FirstGroup (FGP 0.54%)
FirstGroup shares have dived 17% to 102 pence on the day that 723 million new ordinary shares were admitted to the market as part of a three-for-two rights issue. The issue, announced with the transport operator's annual results on May 20, was priced at 85 pence and should raise approximately £615 million -- and on the day of the announcement, the share price slumped by 30%.

The rights issue is intended to "remove the constraints of the current balance sheet and enable the business to continue to invest for future returns, while reducing leverage," and it came hand in hand with a "rebasing" of the dividend.

Britvic (BVIC 0.90%)
Shares in soft-drinks maker Britvic have fallen 1.7% after the Competition Commission gave a provisional go-ahead for the firm's planned merger with A.G. Barr. The deal, apparently, "is not expected to result in a substantial lessening of competition." A final decision is expected by the end of July.

Meanwhile, Barr's share price is down 0.3%, having fallen about 15% over the past couple of weeks.

Oxford Instruments (OXIG 1.20%)
Final results sent Oxford Instruments shares down 6.6%, even though the maker of high-precision tools saw revenue grow by 4% to £351 million, with adjusted pre-tax profit up 14.8% to £48.2 million.

Adjusted earnings per share rose 10.9% to 68.3 pence, and a final dividend of 8.15 pence per share was declared, taking the full-year payment up 12% to 11.2 pence per share.

The firm is now into the final year of its three-year "14 Cubed" plan, and chief executive Jonathan Flint admitted that the year had gotten off to a slow start -- which is probably the reason for this morning's unenthusiastic market response.

Finally, reliable dividends can more than compensate for the day-to-day ups and downs of share prices. So how about a company that's offering a 5% yield and could be set for some nice share-price appreciation, too? It's the subject of our brand-new report "The Motley Fool's Top Income Share For 2013," which you can get completely free of charge -- but it will only be available for a limited period, so click here to get your copy today.