Spike in office building operating expense pass-throughs with office building values in some submarkets space. In some states the real estate property taxes can double, causing a huge financial hit to the tenant. If a building which was previously valued at $300 / sf sells for $600 / sf, the increase in property taxes could be as much as $375 / year, or a monthly rent spike of $.31 / sf. Few landlords are willing to cap this property tax increase exposure as, using a 6% cap rate as an example, the per square foot value of this $3.75 / rsf year expense is roughly $67.50 per building foot. Sounds small, but for a 100,000 sf building the value differential works out to $6.25 million!