Citigroup executives are understood to be weighing up the sale of all or part of its operations, including the Smith Barney brokerage, the credit card unit and the tranaction services unit after its stock lost 50% this week, Wall Street Journal said late Thursday, citing sources familiar with the issue.

The bank has lost more than one-quarter of its value on mounting concern over the capacity of the bank to withstand billions of dollars of potential losses and despite new support from its biggest individual investor, Saudi Prince Alwaleed bin Talal, who plans to increase his stake in Citigroup from 4% to 5%, The Washington Post reports.

Internal discussions are said to be at a preliminary stage, and a formal board meeting is set for today, but Vikram Pandit, Citi chief executive, is reportedly reluctant to sell units.

Citigroup is not commenting on the report, maintaining it has a 'very strong capital and liquidity position' and a strategy which is expected to generate benefits 'over time'.

Further reading:

Citi CFO issues new writedowns warning

Read The Wall Street Journal story

Read The Washington Post story