LONDON—BP P.L.C. expects to contribute $1 billion to its worldwide defined benefit plans this year, according the company's annual report issued Friday.

A breakout of the expected contributions between its U.S. and U.K. plans was unavailable, but it could be similar to last year's split among BP plans, spokesman David Nicholas said.

Last year, the London-based company contributed $795 million to its Warrenville, Ill.-based U.S. defined benefit plans, $9 million to its U.K. plans, and a combined $204 million to its plans in other countries, the report said.

The distribution “will depend on what happens to investments that make up those plans,” Mr. Nicholas said.

As of Dec. 31, BP's U.K. plans had $22.5 billion in assets; U.S. plans, $5.8 billion; and plans in other countries, a combined $3.1 billion. The U.K plans had $21.4 billion in liabilities; the U.S. plans, $7.5 billion; and plans elsewhere, a combined $8.1 billion.

BP will close its U.K. defined benefit plans to new hires as of April 1, except for some joining from North Sea operations who will continue to be eligible to participate in the plans, the report said. The plans will remain open also for employees who joined BP before April 1. “We feel it's necessary competitively to keep the defined benefit plan in place” for the North Sea employees, Mr. Nicholas said.

BP is creating its first U.K. defined contribution plan for employees as of April 1. The company will contribute 15% of pay this year into a flexible benefit program, which includes the new DC plan, private health insurance and cash payout.

Participants can distribute their contribution in any manner they choose each year, such as splitting it up among each of the choices, or putting it all in the DC plan or taking it all in cash, Mr. Nicholas said. The cash takeout would be taxable, Mr. Nicholas said.

The DC plan’s investment management structure and an estimate of the amount expected to be contributed to it were unavailable.

BP contributed $205 million to its U.S. 401(k) plans last year, compared with $170 million in 2008, the report said.

The BP U.S. 401(k) plan had $8 billion in assets as of Sept. 30, according to Pensions & Investments’ directory of the largest U.S. retirement funds.

Barry B. Burr is the editorial page editor for Pensions & Investments, a sister publication of Business Insurance.