By Margot Patrick 

Barclays PLC on Thursday told staff to get ready for changes at its investment bank as it becomes a smaller, more-focused entity to adapt to tougher regulatory and economic conditions.

Barclays earlier Thursday said it would lay out plans on May 8 to improve returns at the unit in a presentation that will also address the broader bank's structure and focus. A review of the investment bank has been under way since last year and is expected by analysts to result in Barclays pulling back in commodities and some areas of fixed income.

In an internal memo to staff seen by The Wall Street Journal, Chief Executive Antony Jenkins said the new plans will address the business areas the bank should focus on, and how to simplify what is now a sprawling organization operating in 50 countries across retail banking, business lending, investment banking, credit cards and wealth management.

"The future for Barclays will be as a strong, focused, international bank. And the investment bank will continue to be a part of that mix," Mr. Jenkins said.

"By early May I am confident that we will have...set a clear course for the next stage of our journey to build a better Barclays which can deliver sustainable returns and growth over the cycle," Mr. Jenkins said.

In a separate announcement Thursday, Barclays said current investment banking co-heads Eric Bommensath and Tom King would turn over some of their responsibilities to three of their deputies, with Eric Felder becoming head of markets and Joe McGrath and Richard Taylor to serve as co-heads of banking. Previously, Mr. Bommensath had been in charge of markets and Mr. King had been head of banking.

The move will strengthen the investment bank's management team and position it for "the next stage of evolution," Barclays said.

Mr. Jenkins is under pressure from shareholders to improve returns after posting a sharp drop in 2013 underlying profit. He said in February the bank would cut around 12,000 jobs, or 9% of its 139,600 workforce, and bring down the size of its balance sheet to meet new regulations.

The investment bank has been the main focus for investors, since it accounts for around two-thirds of the bank's total assets but produced 38% of revenue last year. Mr. Jenkins drew criticism for raising bonuses in the division despite a year-on-year drop in revenue and profit, an issue that is likely to be raised by shareholders at the bank's annual meeting on April 24 in London.

Barclays will post first-quarter results on May 6. Analysts say those are likely to reflect a broader industry decline in revenue from fixed-income trading.

Write to Margot Patrick at margot.patrick@wsj.com

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