FRANKFURT (Reuters) - Germany's second biggest lender, Commerzbank , is planning to slash jobs but also make an investment of 1 billion euros in its struggling retail unit, two sources close to the bank said on Wednesday.

The bank has not yet decided how many jobs will be shed the sources said, after a German paper reported that up to 6,000 jobs are to be axed.

Commerzbank, which is set to announce details of its newest strategy revamp at an investor day on Thursday, declined to comment on the report. (Reporting by Alexander Huebner; writing by Arno Schuetze)