NEW YORK (CNN/Money) - Calm returned a day after WorldCom roiled the markets with news of apparently fraudulent accounting. Buyers returned too -- for the most part.

All three major market indexes traded higher on Thursday. And financial and telecom shares, hit particularly hard on Wednesday, bounced back. (See "WorldCom's ripple effect" for more on the risk WorldCom poses to the financial sector).

But cable and media companies were pummeled for a second straight day. Shares of Charter Communications (CHTR: Research, Estimates) fell 7.8 percent. Insight Communications (ICCI: Research, Estimates)' stock was off 14.6 percent. And Cablevision (CVC: Research, Estimates) plunged 15.3 percent.

Comcast (CMCSK: Research, Estimates) finished the day slightly lower while AOL Time Warner (AOL: Research, Estimates) (owner of CNN/Money) and Cox Communications (COX: Research, Estimates) were relatively flat. Many of those companies had dropped around 10 percent on Wednesday as well.

Companies in the cable sector tend to carry a lot of debt, and like WorldCom (WCOM: Research, Estimates), are typically judged according to EBITDA. Unlike "net income", EBITDA (earnings before interest, taxes, depreciation and amortization) does not get penalized by large capital investments (like telecom networks and cable systems).

In the past, EBITDA numbers were subject to little criticism but post-WorldCom, investors are worried. WorldCom misstated EBITDA by reporting $3.8 billion in expenses as capital expenditures.

Cable and media stocks       AOL Time Warner (AOL) Clear Channel Comm (CCU) Comcast (CMCSK) Cox Communications (COX) Cumulus Media (CMLS)

"The WorldCom case does prove you can fudge any number you want," says Ryon Acey, a cable analyst with BB&T Capital Markets. "This has spooked the market because it calls into question the credibility of EBITDA."

Due to accounting worries, Angela Kohler, manager of the Federated Large Cap Growth fund, says investors have become non-discriminating, unfairly punishing other media companies, such as radio broadcasters Clear Channel Communications (CCU: Research, Estimates) and Cumulus Media (CMLS: Research, Estimates).

Clear Channel was down 12.7 percent on Thursday and Cumulus sank 15 percent. (Radio stocks also faced pressure on Thursday due to news of a bill introduced by Democratic Sen. Russell Feingold that calls for more regulation of the radio industry.)

Radio companies are also judged primarily by EBITDA because they have expensive radio licenses and big-ticket equipment, both of which depreciate or can be amortized. But Kohler says that the fundamentals of radio companies are improving as advertising rates firm, and she thinks the selloff is overdone.

Still, the media bloodbath of the past two days hasn't convinced Kohler that it's time to buy. Even though she doesn't think there will be many instances of EBITDA-related accounting fraud, that doesn't seem to matter in this skittish environment.

"Although things might be OK fundamentally, sentiment doesn't turn that quickly," Kohler says. "I don't want to be the first brave person to buy."