Rising commercial real estate rates, a gauge that brokers use to determine the strength of the housing market, are likely to deter many new homeowners from buying houses this spring.

Hi Yogender,

You are correct that when verb-ing word acts as subject of the clause, the verb is always singular. For example:

Swimming is fun.
What is fun? Swimming. So swimming is the subject.

Singing has a therapeutic effect on people.
What has therapeutic effect on people? Singing. So singing is the subject.

Protecting the country from the rule of traitors is the goal of the commission.
What is the goal of the commission? Protecting the country...= Subject

In the above sentences, "verb-ing word" presents an action. swimming, singing, protecting

Now lets consider this sentence:

Pink dolls are very popular in China.
What are popular - pink dolls. So pink dolls = subject.
Note here that "pink" is an adjective describing the dolls.

Singing dolls are very popular in China.
What are popular - singing dolls. So singing dolls = subject.
Here again "singing" is an adjective describing dolls.

So as you can see, verb-ing word can play different roles. So the key is to determine if this word simply describes the associated noun or if it actually signifies an action that can act as the subject of the verb. (In grammatical terms - whether it acts as participle or gerund).

Now lets come to the sentence in question:

Rising commercial real estate rates, a gauge that brokers use to determine the strength of the housing market, are likely to deter many new homeowners from buying houses this spring.

Here "rising" is an adjective. It describes the real estate rates. So our actual subject is the noun - rates and hence the plural verb "are".

Thanks,

Payal