Starwood Property Trust originated a $126 million first mortgage and mezzanine loan on behalf of Blackstone Real Estate Partners VII for 100 Montgomery, a 20-story, 420,000-sq.-ft. class-A office building in San Francisco’s Financial District.

The total financing will have initial funding of $115.5 million, with $10.5 million in future funding for tenant improvements and leasing commissions. The loan features an interest rate that floats over LIBOR and a three-year term with two one-year extension options. Starwood plans to sell the first mortgage in the near term to increase its return on investment while retaining the mezzanine portion of the financing.

100 Montgomery is located on the corner of Sutter and Montgomery Streets. It underwent a $54 million capital improvements project in 2009 that included a new crystallized glass façade, lobby and common area updates and new retail storefronts. The building also achieved LEED Gold certification.

“We are excited to complete another complex financing transaction with Blackstone,” said Starwood Property President and Director Boyd Fellows. “Similar to the $61 million Glendale transaction we announced earlier this quarter, we funded the entire capital stack with a flexible structure which meets Blackstone’s exact financing needs.”