Insufficient supply for shorts

Tried to short qqqq the other day and got the message. How do you tell ahead of time?

 

You get the little red field on the IB TWS field that's normally green. GM was red last week, but I've never seen QQQQ red.

Just go long QID next time.

 

thanks, just I don't go through IB, anywhere else for the little red light?

Not gonna go long QID as it's backed by a lot of CDS', they're shaky.

 

Damn, what's up with QQQQ not shortable again? I've never seen this before.