The Bloomberg tab should appear as one of the menu items in Excel. If it is not there, you may need to reinstall the add-in. This may be due to an update on the computer you are using.
If the Bloomberg tab is not visible in Excel, you can install it using the following steps:
Close all Excel spreadsheets and follow this path: Start > All Programs > Bloomberg > Install Excell Add-in
Once installed, the Bloomberg tab will appear in the Excel ribbon.
If there is an error in installation, run Start > All Programs > Bloomberg > Bloomberg API Diagnostics > Start & Repair, and try to install the add-in again.
