Guarantee Mortgage - San Francisco, 505 Montgomery

We have helped Bay Area families finance their home purchase, with over $2 billion in loans annually, and we can help you.

Offering a wide range of products and services, Guarantee Mortgage is well prepared to meet every real estate lending need.

We have 22 years under our belt providing world-class client service. Our top priority is to make sure you are presented with all available loan options, so that you can make an informed decision, that’s right for your financial situation.

Guarantee Mortgage NMLS #1850 and CAL-BRE License #01215943


Recommendations (1151)


David B. recommends Fe David

Quick and painless

Robert H. recommends Robin Patronik

Robin has always looked after our interest, not just one time but on a continual basis.

Douglas W. recommends Joel Marks

Joel was great. Very knowledgeable, always got back to us in a timely manner and we are happy with our new mortgage.
3 days ago

David Fowler recommends Kathy Derangi

Kathy managed to get us an incredibly low interest rate. And even though the folks at escrow were not following through on their end, Kathy did some important butt-kicking and got the loan to close even though it looked like it might be delayed, which would cost us extra money. She's a mild-mannered bulldog, which certainly helped in our case.
Jul 8, 2020

Dmitry Martynov recommends Orlando Diaz

I had a pleasure of working with Orlando on two occasions, one purchasing my first home and two helping my family refinance. Neither of the two were quick and easy, but Orlando took on the challenge and helped us tremendously. It is always a pleasure to work with him and I would recommend him to anyone in a heartbeat!
Jul 7, 2020

Patty Domenickine recommends Larry Horowitz

I can easily recommend using Larry for your loan needs. Larry is a great communicator, easy to work with and someone you can trust.
Jul 5, 2020

Sunita Rao recommends Aisling Ferguson

I highly recommend Aisling Ferguson. If you want to work with someone who will go the extra mile to get it done, she is your gal. We had scheduled to close on the 30th of the month. Aisling brought to my attention that an earlier close was possible and diligently managed the process to make it happen. She was very attentive - always responding to my questions with patience and promptness. Getting me an early close was not critical to the transaction but it made a big difference to me - saving me both from unwanted expense and unwanted stress.
Aisling, I cannot thank you enough!
Jul 3, 2020

Alex A recommends Kathy Derangi


We really appreciate Kathy's transparency and genuineness. She was open to listen to our situation and she made every effort to offer the best deal. It seemed like we had a question everyday and she responded immediately. It totally eased our concerns. Thank you!
Jul 2, 2020

Cecily Jaros recommends Aisling Ferguson

Aisling was absolutely incredible to work with as we navigated purchasing our first home (a success undoubtedly because of her help!). When we first began our home hunt process, Aisling hopped on the phone with me to discuss how we’d partner together, and as our hunt grew to be more serious, educating me throughout and available and prompt always. Once your offer is accepted, the fun begins and Aisling shines. She helped us through every step of the process, always a phone email or text away. She kept track of timelines and navigated when and how we were to stay on track. Aisling is a superb advocate for her clients, expert in the field, and a warm and knowledgeable professional to work with. I can not recommend her enough!
Jul 1, 2020

Peggy O. recommends KC Murphy

KC Murphy is always great to work with. His professionalism and consistent communication was appreciated throughout the refinance process. We feared the COVID19 situation would adversely affect our ability to refi but it was as smooth as could be.
Jul 1, 2020

Hermes L. recommends Fe David

Fe David is a very reliable employee of your company. Very fast on responding to all the. transactions. Meets the deadlines and very efficient on follow ups. I couldn’t ask for another agent but only her on doin business with your company.
Jun 30, 2020

Sarah Larkin recommends Robin Patronik

Robin has handled several refinances for us and makes the difficult process as easy as possible. She has our recommendation!
Jun 30, 2020

Michael K. recommends Aisling Ferguson

Fantastic as always!
Jun 28, 2020

Mike K recommends Aisling Ferguson

We've worked with Aisling multiple times since 2008. She's always fantastic to work with: organized, knowledgeable, professional. Thank you!
Jun 25, 2020

Mike Schramm recommends Mark Wiener

Vice President eCommerce

I had contacted Mark a few months ago to assess the process of applying for a first home mortgage. I had not applied for a mortgage since 2006 and I knew a lot of things had changed after the 2008-2010 real estate and loan crisis.

Mark walked me through the process and got me oriented on what lay ahead. He encouraged me to get the application process going quickly, "as you never know.". Well I didn't heed that advice. We went shopping for a house, thinking it was early days and not time for us to buy. Not the case. On May 22, our first day looking at houses, we found the one we wanted and made an offer.

After contacting Mark, and him giving me the polite and light-hearted "I told ya." We were off and running. I'm happy to say that yesterday, June 24th we closed escrow and our loan funded.

We could not have done it without Mark and his team's expertise. I will caution you, there's a lot of paperwork to process if you have not applied for a loan in some time. Mark guided us through it, and with a little help from a secured shared drive in the cloud, and e-signatures, we got it done!

We got a great rate. Mark worked great with all parties, the realtors and the title company.

I highly recommend Mark and his team to find the right financing for your house purchase.
Jun 23, 2020

Winton8 recommends Aisling Ferguson

We had a very short loan contingency, but Aisling got it done. She was a step ahead throughout the process. No hiccups. Got it done. Aisling is a pleasure to work with.
Jun 22, 2020

P.P. recommends Aisling Ferguson

I've been through several refinances and my experience with Aisling was the best. I was able to do all my paperwork online and even scheduled the final signing online. This was very important since we did this during the height of the COVID-19 pandemic when face-to-face contact was difficult.
Jun 22, 2020

Kurt G. recommends Aisling Ferguson

Just finished a refi with Aisling this week (5/26) and am extremely happy with the service she has provided. This was my second time working with her and I give her the highest marks possible for communication (always quick to respond and to update me) as well as options offered in the various loan vehicles. Everything went very smoothly and I continue to recommend her to all of my friends. She did a simply superb job on this most recent loan.
Jun 22, 2020

cenorton61 recommends Aisling Ferguson

This is the second time we used Aisling to refi our home. The first time she was able to get us a jumbo loan when no one else would. This time - right in the midst of the COVID-19 pandemic - she worked her fingers to the bone to ensure that we got funded. The investors put every obstacle you could think of in her way - but she advocated ferociously on our behalf and we closed two days ago. When times are tough - you want Aisling on your side.
Jun 21, 2020

Cassandra Seebaum recommends Aisling Ferguson


Absolutely recommend Aisling - fantastic! We worked with Aisling on our refinance and she was knowledgeable, clear, concise, organized, and so diligent - a real expert and leader in her field. Aisling guided us through every step of the way and made us feel like her most important client. Our situation was complex and she never gave up - definitely putting in extra time to make sure we got our loan. For her expertise 5 star - customer service 5 star - ability to close 5 star!
Jun 19, 2020

John W Richards recommends Orlando Diaz

You know how some people make you feel as if you are their only client even though they have many business activities going on? Well, that is Orlando. He constantly kept us up to date on things, guided us through required paper work, kept tabs on our transaction, and made us feel like we were his only clients. He pulled off a miracle to first get us into our house, and now helped us refinance. If you want the best, you want Orlando.
Jun 17, 2020

Troy Onorato recommends Ken Dean

Thoroughbred Horses Owner

Ken Dean was excellent to work with. Was able to understand my business and maneuver superb explaining it to lenders. I am a happy house owner for the next 15 years. I would highly recommend him to other home owners and potential home owners.
Jun 16, 2020

Maritza O. recommends Ken Dean

Ken was very helpful and on top of things. Made the whole process easy to understand and deal with.
Jun 12, 2020

Marco V. recommends Kathy Derangi

This is the 2nd refinance that I have done with Kathy and of course it was a wonderful experience! Kathy and I understand my expectations, my goals and executes efficiently and effectively. This is why Kathy has been a strong partner of mine since 2015!
Jun 10, 2020

Sothy L. recommends Larry Horowitz

Wow the whole process was much quicker and easier then I anticipated. Great job Larry.

Our Team

  • Bob Siefert

    Senior Vice President - San Francisco - Montgomery St.
    NMLS #55105 / 1850 - CA BRE #00921214 / 01215943

  • Orlando Diaz

    Sr. Loan Consultant - San Francisco - Montgomery St.
    NMLS #238849 / 1850 - CA BRE #01475255 / 01215943

  • Foster Weeks

    Loan Originator - San Francisco - Montgomery St.
    NMLS #253370 / 1850 - CA BRE #01383598 / 01215943

  • Allan McAllister

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #280540 / 1850 - CA BRE #01372084 / 01215943

  • Aisling Ferguson

    NMLS #280915 Loan Consultant - San Francisco
    NMLS #280915 / 1850 - CA BRE #01225420 / 01215943

  • Kevin Casey

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #238192 / 1850 - CA BRE #01178612 / 01215943

  • Mireille Costandi

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #249322 / 1850 - CA BRE #01132350 / 01215943

  • Ken Dean

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #237940 / 1850 - CA BRE #0902556 / 01215943

  • Larry Horowitz

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #239001 / 1850 - CA BRE #01003870 / 01215943

  • Amy Lai

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #341535 / 1850 - CA BRE #01795977 / 01215943

  • Ming Leong

    Loan Consultant - San Francisco - Montgomery St.
    NMLS # 252471 / 1850 - CA BRE #01369831 / 01215943

  • Natasha Lovas

    Senior Mortgage Advisor - San Francisco - Montgomery St.
    NMLS #239455 / 1850 - CA BRE #01161948 / 01215943

  • Paul Rea

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #280163 / 1850 - CA BRE #00856755 / 01215943

  • Cecelia Tyeskey

    Reverse Mortgage Specialist - San Francisco - Montgomery St
    NMLS #239861 / 1850 - CA BRE #01212004 / 01215943

  • James W. Argo

    Senior Loan Officer - San Francisco - Montgomery St.
    NMLS #257031 / 1850 - CA DRE #00869591 / 01215943

  • KC Murphy

    Sr. Loan Consultant - San Francisco - Montgomery St.
    NMLS #255492 / 1850 - CA BRE #1007053 / 01215943

  • Robin Patronik

    Senior Loan Officer - San Francisco - Montgomery St.
    NMLS #241087 / 1850 - CA BRE #01347330 / 01215943

  • Sally Adam

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #245703 / 1850 - CA BRE #01244582 / 01215943

  • Sheila Wood

    Manager/Loan Consultant - San Francisco - Montgomery St.
    NMLS #253742 / 1850 - CA BRE #00824166 / 01215943

  • Kathy Derangi

    Loan Consultant - San Francisco - Montgomery St.
    NMLS #1151839 / 1850

  • Risa J. Meyer

    Mortgage Specialist - San Francisco - Montgomery St.
    NMLS #332214 / 1850 - CA BRE #01126851 / 01215943

  • Joel Marks

    Loan Advisor (NMLS: #216888/1850)

  • Fe David

    Loan Consultant - San Francisco - Montgomery St.
    NMLS # 482592 / 1850 - APMC CA BRE #01215943

  • Mark Wiener

    Loan Officer - San Francisco - Montgomery St.
    NMLS # 246293 / 1850 - APMC CA BRE #01215943

  • Pov Oum

    Loan Officer-San Francisco-Montgomery St.
    NMLS # 1226687 / 1850 - APMC CA BRE #01215943

  • Tra Thach

    Loan Consultant