That’s because, in English, that tense should actually be “banks have planned”. It doesn’t make these options any less correct. If you want to use “banks plan”, just put “now”
The idealized formulation of this sentence would be “thenceforth, banks planned for this tactic”, “since then, banks have planned for this tactic”, or “banks plan for this tactic now”
“Since then,” “thenceforth”
nope. both specific.
doesn’t work
That’s because, in English, that tense should actually be “banks have planned”. It doesn’t make these options any less correct. If you want to use “banks plan”, just put “now”
The idealized formulation of this sentence would be “thenceforth, banks planned for this tactic”, “since then, banks have planned for this tactic”, or “banks plan for this tactic now”