～は～となっている【は～となっている】

[A] は [B] となっている states how A is set or how it stands: a fee, a deadline, a rule, a figure. B is a noun – often an amount, a time or a word like きんし禁止 or むりょう無料 – and となっている is となる in the ている-form, a state that has come about and holds now.

English uses a plain "is" here. Reading となっている as "is becoming" is wrong: the change is over, and what is left is the current arrangement.

Figures and statistics

News and reports give numbers with となっている – what a figure stands at now.

となっている or になっている

Both describe a set arrangement. となっている sounds official and fixed, and belongs to notices, rules and reports; になっている is the everyday form, and the one to use in conversation.

Register

Signs and shop staff use the polite となっております to tell customers how things are.