Time Warner Cable has reached a deal to buy The Carlyle Group's cable operator Insight Communications Co for around $3 billion in cash, a source familiar with the matter said on Sunday.

Time Warner could announce the deal as soon as Monday morning, the source said.

Insight is the 10th-largest cable operator in the United States, Carlyle's website says. It sells cable television, high-speed Internet and telephone services, serving around 750,000 customers in Illinois, Indiana, Kentucky and Ohio.

Insight representatives approached Time Warner in recent weeks to discuss a deal after failing to reach agreement with other strategic and private equity bidders, the source said.

TWC had dropped out of an auction for Insight earlier this year, because the company believed Carlyle was asking for too much, a source told Reuters in May. Carlyle had originally been looking for around $4 billion, sources said then.

Executives at Time Warner Cable have regularly said that any acquisition targets would not be valued at a higher multiple than its own stock.

This is Time Warner Cable's largest acquisition since it was spun off from former parent Time Warner Inc in 2009. Earlier this year it paid $260 million for NewWave Communications, a small cable operator with cable systems also in the Midwest.

The deal could enable Time Warner Cable to reap programing cost savings, tax benefits as well as other operating synergies. Insight owns cable systems that are contiguous to Time Warner Cable's in the Midwest United States including states of Ohio, Kentucky and Indiana.

Time Warner and Carlyle declined to comment. Insight could not be immediately reached for comment.

Shares of Time Warner Cable closed at $65.51 on Friday.

(Reporting by Yinka Adegoke, Writing by Michael Erman; Editing by Dale Hudson and Muralikumar Anantharaman)