ought to (ellipsis) – English Grammar Profiler

Point 145 in the category of MODALITY and ELLIPSIS is defined as:

‘ought to’ without a following verb where the previous main verb is understood.

There is an important note in the comments section of the EGP:

This is a very low-frequency form in both the learner and native speaker data.

There’s only one example in the TED corpus:

But as I said earlier, this kind of logic applies across the board for infectious diseases, and it ought to.

A search for collocates up to 4 spaces to the left of ought to.

1 THEY (PPHS2 ) 210

2 THAN (CSN ) 128

3 THINK (VV0 ) 47 4 REALLY (RR ) 42

5 WAY (NN1 ) 39

*google search does not allow a search for the full stop.  This makes it very hard to find examples of it.