De or het indexstijging?

The correct Dutch article is:

de indexstijging

Rule Words ending in -ing: almost always de. See the rule

How to use indexstijging

the indexstijgingde indexstijging
this indexstijgingdeze indexstijging
that indexstijgingdie indexstijging
our indexstijgingonze indexstijging
your indexstijgingjouw indexstijging
every indexstijgingelke indexstijging
which indexstijging?welke indexstijging?
a big indexstijging / the big indexstijgingeen grote indexstijging, de grote indexstijging