joining me for a look at how bloombergforming is interest-rate's senior research analyst.an explosion these being built. is there enough demand yet to fill that office base? >> thank you for having me. i think so. the reason is most of the building is happening in a couple of markets. it is markets like new york and san francisco where the demand is being driven by technology jobs. san francisco alone, you have companies like boston properties, and a lot of what they're building, it is expanding like crazy in that market. will continue to see that. the buildings underway are largely policed ahead of time. it mitigates a lot of the risk. >> what is the risk? even if there is a demand, or at least a risk of overbuilding, right? >> there is. that is light landlords are wise to get a lot of the leasing them before the buildings come out of the ground. one of the things we saw in the last cycle in san francisco especially coming out of the tech boom in the early part of the century was too much construction. a lot of companies went under. rents and occupancy's tank. that is the