Suppressing an unwanted new tab in Safari

Solution 1:

There are probably more elegant solutions! But in the absence of those, I would write a macro to monitor and immediately close the tab.

Pseudocode:

• In Safari, whenever the focused window's name changes:
  • (maybe wait a fraction of a second)
  • If the name is [name of credit score page]:
    • Select menu item File > Close Tab.
      (or hit ⌘W, or run an AppleScript)

This may be similarly achievable using other macro programs, but here's how it looks in Keyboard Maestro: (this macro would be placed in a group designated to be active only in Safari, or in all web browsers, to minimize impact)