Lease negotiations for option period

[Bharath Raj]

Our brokers negotiated a commercial office lease with a national tenant in the LOI. A draft of the lease was drawn and the contract was prepared by my attorney. The tenant' attorney reviewed it and sent it back with several edits. The original agreement was to let the tenant have a 3 year lease with one additional 3 year option at the market rate at the time. However, the tenant' attorney now wants to fix the rent for the optional 3 years right now. This property has been difficult to lease so far. I am inclined to work with this tenant, but I do feel like I don't want to get into a second round of negotiations. Is there a rule of thumb that can be used, ex: a 10% increase in base rents for year 4 when compared to year 1 rents, and then 3% subsequent increases for years 5 and 6? Any guidance would be greatly appreciated