ITV, Britain's biggest privately owned broadcaster, will pay shareholders a special dividend of £156m after posting solid full year results amid continued speculation of a takeover bid.

The London-based media group said earnings grew 13 percent from last year to £520m on total revenues of around £2.2bn, in a statement published on its website. The board proposed a final full-year dividend of 1.8 pence for each share - a 50 percent increase - and a special dividend of worth 4 pence for each share. The group said it expects a 5 percent increase in first quarter advertising revenue for this year.

"Over the last three years we have consistently grown our revenues, delivered double digit earnings growth and converted that earnings growth to cash to strengthen our financial position. During that time we have increased our profits by 157 percent to £520m," said CEO Adam Crozier in the statement. "While there is still much to do this is clear evidence that ITV is transforming into a more robust, efficient and balanced company."

The stock has been trading within touching distance of a five year high for the past two weeks on continued speculation that the recent $16m takeover of Virgin Media by US billionaire John Malone will spur a similar move for ITV, the most popular commercial channel in the United Kingdom.

RBS credit analyst Paul Crawford called the special dividend payment "a potential defence against, the recent press speculation that the company could be subject to a (private equity) buyout" in client note published Monday. "Whilst the payment of a special dividend will increase the net debt of the group and reduce potential cash available for a bond buyback it is also likely to reduce the attractiveness as a target."

Crozier told investors on a conference call shortly after the earnings statement that ITV has not received any approaches from private equity firms.

ITV shares rose 1.33 percent in early London trading to change hands a 121.8 pence each, the highest level since at least 2007. The shares have risen 15.8 percent so far this year.