LOS ANGELES — Comcast has agreed to buy Time Warner Cable for $45.2 billion in stock, or $158.82 per share, two people familiar with the matter said late Wednesday.

The deal will combine the nation’s top two cable TV companies and make Comcast, which also owns NBCUniversal, a dominant force in both creating and delivering entertainment to U.S. homes.

The deal was approved by the boards of both companies and, pending regulatory approval, is expected to close by the end of the year, the people said.

The price is about 17 percent above Time Warner Cable shares’ Wednesday closing price of $135.31 and trumps a proposal by Charter Communications to buy Time Warner for about $132.50 per share, or $38 billion in cash and stock.

Time Warner Cable shareholders will receive 2.57 Comcast shares for every Time Warner Cable share they own. Once the deal is final, they will end up owning about 23 percent of the combined company, one of the people said.

Charter had pursued Time Warner Cable for months but Time Warner Cable CEO Rob Marcus had consistently rejected what he called a lowball offer, saying he’d cut a deal for $160 per share in cash and stock.

For a time, Comcast stayed in the background, waiting to purchase any chunk of subscribers that a combined Charter-Time Warner Cable would sell off. Charter had planned to finance its bid with $25 billion in new debt. As part of a plan to pay off the debt quickly, the company considered selling off some of its territories after a deal had closed. Time Warner Cable’s Marcus had also balked at the huge debt burden the Charter takeover represented.