That's the number in the week after the announcement, by my reading.

> Amazon announced last week that it would be splitting its second headquarters between Long Island City in Queens and Arlington County, Va., ending months of jockeying between cities and speculation of where the tech giant would land.

> There are no exact numbers on how many units have gone into contract in the Long Island City area since the announcement, but the Journal reports that one brokerage firm sold nearly 150 units just last week, 15 times its normal volume.

I personally find that claim dubious since I don't think there are 150 units available in all of LIC and it takes a non-trivial amount of time to buy a condo. So for 150 to sell in a week that means there must be 300+ in flight which is basically impossible. Plus for a single firm to do that means there must be, what, 5x as many across other firms which comes out to 1500+. I somehow doubt that 20+% of LIC's total condos are in the process of being sold within a few weeks.