A report investigating TSB's technology meltdown will be fast-tracked and published before the end of the year.
Law firm Slaughter and May is conducting an investigation into a botched IT systems migration in April that left customers unable to access online bank accounts.
The report will be divided into two sections, with the first half focused on the IT migration and published before Christmas and the second section investigating TSB's handling of the aftermath, to be published next year.
Chief executive Paul Pester stepped down with a £1.7m payout last week as customers continued to face issues five months on from the meltdown.
TSB executive chairman Richard Meddings commented: "We also are running a review that the Board of TSB commissioned, which is by Slaughter and May.
"With that, we have determined to make sure we can get information out as soon as practicable.
"We are probably going to divide that in two essential chapters, so we are dividing the report into two elements.
"That should enable us to produce the first part of that hopefully before the end of this year.”