MOORESVILLE, N.C. (AP) _ Dale Earnhardt Jr. will leave the company founded by his late father at the end of the year in a shake-up certain to ignite a bidding war for NASCAR's most popular driver.

He told Dale Earnhardt Inc. on Thursday that he had decided to make the switch to another team when his contract expires, intent on going to a more competitive team.

``At 32 years of age, the same age my father was when he made his final and most important career decision, it's time for me to compete on a consistent basis and contend for championships now,'' Earnhardt said at a news conference. ``I believe I'd have my father's blessing.''

Earnhardt had asked for 51 per cent ownership of the team now run by his stepmother Teresa. Negotiations on a contract extension began before the season and have been tense all along. Earnhardt's sister Kelley Earnhardt Elledge had set a deadline to get the deal done by the end of the month.

``We never even got close,'' Earnhardt said.

He stressed money is not the issue.

``It's not the guy who gives me the biggest paycheque. It's the person I feel like will allow me to accomplish what I want to in my career, on the race track, in this shop itself, he said. ``There's some things you can't get with money, peace of mind and satisfaction in what you do everyday. ... I'm seeking to have that peace of mind and that comfort to be able to really be an asset to somebody. I want to go somewhere and really make things happen for somebody.''

Sitting next to his sister and wearing a T-shirt and an open collared shirt, Earnhardt said he leaves DEI with mixed emotions.

``I'm sad that I have to leave some employees that I got close to, leave some relationships,'' Earnhardt said. ``We're going to finish this year out, and I told my guys we're going to run hard. I don't want any excuses for us not giving our best effort. I plan on giving everything I've got like I always do, and hopefully that's what I'll get in return.''

In a statement, Teresa Earnhardt said DEI will thrive following Junior's announcement.

``While we are very disappointed that Dale Jr. has chosen to leave the family business, we remain excited about our company's future,'' she said. ``Dale and I built this company to be a championship contender, and those principles still apply. Dale Earnhardt Inc. will win. ... This company has a great legacy and a bright future, built on loyalty, integrity and commitment.''

Now, Earnhardt must decide which team is the best fit for him. He said he would like to continue to drive Chevrolets, which will limit his options. It's also likely his primary sponsor, Budweiser, will move with him to the new team.

``I believe our first choice would be to drive for another top, competitive team,'' Earnhardt Elledge said. ``Our last choice would be to form our own Cup team. If that was necessary, that would be what we would do.''

``We're going to listen to everybody,'' Earnhardt added.