CBS shares decline as Lehman cuts to 'Underweight'

Shares lost 53 cents, or 2.9 percent, to $18.07. Shares hit a fresh 52-week low of $17.86 earlier in the session.

Anthony DiClemente said revenue declines in CBS's radio division have quickened since 2007 and the trend does not appear set to change.

Meanwhile, DiClemente estimates core advertising revenue at CBS's TV stations declined 8 to 9 percent in the first quarter, and he expects difficulties at the company's network and stations to continue in the near term.

He also said the company's recent $11.50-per-share acquisition of Web site operator CNet Networks Inc.--an acquisition that DiClemente said raises many unanswered questions--signals that CBS may be looking to make further purchases, particularly given its strong balance sheet.

The CNET deal closed June 30, according to CBS.

DiClemente cut his price target to $16 from $25. He lowered his rating from "Equal Weight." A CBS spokesman declined to comment on the downgrade.

Separately, the analyst downgraded the broader entertainment sector to "Negative" from "Neutral," citing concerns over the effect of digital content distribution.

On Friday, shares of CBS fell 13 cents to close at $18.60. The stock has declined by nearly a third since the start of the year.