Den effektive renten falt såpass mye at terminbeløpet ble lavt.

This is the normal Norwegian pattern for a definite noun with an adjective in many cases. It is often called double definiteness.

• rente = an interest rate
• renten = the interest rate
• effektiv rente = effective interest rate
• den effektive renten = the effective interest rate

So when a noun is definite and has an adjective before it, Norwegian often uses:

den/det/de + adjective + noun in definite form

Examples:

• den store bilen = the big car
• det nye huset = the new house
• de gamle bøkene = the old books

That is why den effektive renten is correct.

Because the adjective comes before a definite noun.

Compare:

• en effektiv rente = an effective interest rate
• den effektive renten = the effective interest rate

In Norwegian, adjectives usually take -e in definite phrases:

• den fine dagen
• det store huset
• de røde bilene

So effektiv changes to effektive because it is part of the definite phrase den effektive renten.

In financial Norwegian, effektiv rente usually means the effective interest rate, often the real yearly cost of a loan when fees and compounding are included. In many contexts, it is close to what English speakers call APR or a similar real annual borrowing cost.

So this is not just any rate. It is a specific financial term.

Falt is the past tense of falle, which means to fall.

Forms:

• infinitive: å falle
• present: faller
• past: falt
• past participle: falt

So:

• renten faller = the interest rate falls / is falling
• renten falt = the interest rate fell

It is an irregular verb, so you just have to learn the form falt.

It means something like so much that or by enough that.

The structure is:

såpass mye at + result

So here:

• Den effektive renten falt såpass mye at ...
• The effective interest rate fell so much that ...

The word såpass adds a nuance of to that extent, that much, or enough for the following result to happen.

It is slightly more idiomatic and conversational than just så mye at, though both can work.

Yes, in many situations you could.

• falt så mye at ... = fell so much that ...
• falt såpass mye at ... = fell that much / enough that ...

The version with såpass can sound a little more nuanced, often suggesting that the amount was enough to produce the result that follows.

So:

• så mye at = very straightforward
• såpass mye at = a bit more idiomatic, with a sense of to such an extent

It is a compound noun:

• termin = installment period / due period / payment term
• beløp = amount
• terminbeløp = installment amount / periodic payment amount
• terminbeløpet = the installment amount / the periodic payment

In loan and mortgage contexts, terminbeløp usually refers to the amount you must pay each payment period.

Like many Norwegian nouns, it is built by combining smaller words into one long compound.

Because Norwegian often forms compound nouns as one word, where English might use two or more words.

So:

• termin + beløp = terminbeløp

This is very common in Norwegian:

• bankkonto = bank account
• rentesats = interest rate
• månedslønn = monthly salary

If you split compounds incorrectly, it can look unnatural or even change the meaning. So terminbeløp should be written as one word.

Because beløp is a neuter noun.

• et beløp = an amount

When an adjective is used after verbs like bli or være, it still agrees with the noun in gender and number.

So:

• et beløp ble lavt
• en pris ble lav
• et hus ble stort
• en bil ble stor

Since terminbeløpet is based on et beløp, the adjective must be lavt, not lav.

In Norwegian, lav is often used for things like levels, rates, prices, and amounts when English might also say low.

So lavt here means low, not physically short.

Examples:

• lav rente = low interest rate
• lav pris = low price
• lavt beløp = low amount

You would not normally use liten here, because liten means small in size or quantity, not low in level or value in the same way.

Because after at meaning that, Norwegian normally uses subordinate clause word order.

Main clause:

• Terminbeløpet ble lavt.

Subordinate clause after at:

• ... at terminbeløpet ble lavt

In subordinate clauses, the subject usually comes before the verb in the normal order.

This is different from main clauses in Norwegian, where the language often follows the verb-second rule.

Here ble is from bli, which usually means become.

So:

• ble lavt = became low

That fits the idea of a change: the installment amount changed and ended up low because the interest rate fell.

Compare:

• er lavt = is low
• ble lavt = became low / was low as a result

In natural English translation, you might not always say became, but grammatically that is what ble is doing.

Because mye is modifying the degree of the verb falt.

The sentence is talking about how much the interest rate fell, not describing a noun directly.

So:

• falt mye = fell a lot
• falt såpass mye = fell that much / fell enough

If you were describing a noun, you might use forms of stor instead:

• et stort fall = a big drop

But here the sentence uses a verb phrase:

• renten falt mye not
• renten falt stor

So mye is the correct choice.