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 (1359)


Eneida O. recommends Kevin Casey

Excellent experience. Kevin is thorough and quickly responded to all of my questions.
3 days ago

Yuen Tung C. recommends Joel Marks

It was so easy to work with Joel from beginning to the end. Everything went so smoothly and we feel confident and trust. Thank you!
Oct 22, 2021

Raina Petrov DVM, MS recommends Orlando Diaz

Real Estate Agent

Lightning-fast! Those are the words that come to mind when I think about Orlando Diaz. However, there is no sacrificing quality here. Orlando is responsive and speedy, but so meticulous, patient, and friendly. He has easily walked my buyers through the complicated lending process giving them all the explanations they need to feel comfortable and has been adaptable when situations change. Orlando has also offered my clients creative solutions to help them achieve their homeownership dreams, even when their financial situations are complicated. He provides a high level of attentive service to all his clients whether they are buying a fixer-upper or a renovated dream home. As a real estate agent, it gives me comfort to refer my clients to Orlando because I know that he will compliment my very high standards of communication-based service, and help my clients feel like they are being supported by a dynamic, skilled team.
Oct 20, 2021

Cody Wallace recommends Pov Oum


Pov did an amazing job with our refinance, and even initially reached out to us to let us know it was the right time to refinance, after helping with us with our first mortgage. Pov, we truly appreciate your guidance and sense of urgency in getting out file closed! We’re now at lower rate and monthly payment, thanks to you. Mission accomplished. Thank you Pov!
Oct 13, 2021

Michelle Francisco recommends Pov Oum

Pov yet again deserves more than five stars! This is the second time working with her and she completed our refi wonderfully! She is communicative, responsive, and detail oriented when it comes to explaining or answering questions. She takes the time to ensure her clients are comfortable and on the same page at all times. She has great ethics as well. She is very prompt on giving us updates to let us know where we are at in the process and her customer service goes above normal standards!! She deserves 10 stars!!!
Oct 12, 2021

Brooke A. recommends Ken Dean

Ken is amazing, he closed our deal so quickly and under lots of pressure -- we will be working with Ken in the future.
Oct 6, 2021

Joanna H. recommends Joel Marks

Wonderful service from the best broker !
Oct 6, 2021

Kristopher S. recommends Joel Marks

Joel was consultative and professional through the entire process.
Oct 4, 2021

Jerry Adan recommends Ken Dean

Ken worked hard to get us the loan. It seems like the lender kept asking for more documentation as the process progressed and he kept on top of everything to help things moved smoothly. It was frustrating at times but we got the loan at a great rate.
Sep 29, 2021

Mark W. recommends Orlando Diaz

Very responsive, took into account my situation given the birth of my son and respected my time and new responsibilities. Would and will recommend.
Sep 28, 2021

Steven H. recommends Joel Marks

Joel did a great job of keeping us on track of a lengthy, tedious closing due to the nature of the underwriting. Once we got final approval things moved Very Quickly and that was much appreciated. 4 days from final approval to keys in hand.
Sep 23, 2021

Rodney Rogers recommends Aisling Ferguson

Always professional, helpful, honest and extremely responsive! Highly Recommended!!
Sep 20, 2021

Lisa H. recommends Ken Dean

Ken went above and beyond what I expected and I would highly recommend him. He makes you a priority and explains every step along the way. I will only be using Ken in any future ventures I have.
Sep 8, 2021

Cristi Iannuzzi recommends Aisling Ferguson

There aren’t enough stars to thank Aisling for always giving us 100%. I’ve lost count of the number of loans/refinances she has done for us now and I’m amazed by her ethic and hard work. Thanks to Aisling that we always get the best deal that can be done.
Sep 3, 2021

Jeffrey Smith recommends Aisling Ferguson

Registered Nurse

Aisling is a professional in every sense. She was on top of our documentation at all times, and kept us fully informed every step of the way with flawless communication. She assisted me with a property purchase more than 15 years ago, and I was thrilled to be able to work with her again for this most recent purchase. I can't recommend her highly enough!
Sep 1, 2021

Robert A Horton recommends Orlando Diaz

co-founder of untraining

Orlando went beyond the call of duty for us as buyers of our home, where we had rented for 30 years. He helped us through sticky situations and crisis. He was friendly helpful and available. I can not say enough positive about him as this was a difficult passage for us and he helped us get through it.
Aug 27, 2021

Sanjay l patel recommends Pov Oum


POV did very good job for she also very fast job done so I very strongly recommend POV
Aug 26, 2021

Jeff Wagener recommends Ken Dean

Ken is a good, compassionate, and proactive partner throughout the process.
Aug 24, 2021

Karen Peterson recommends Mireille Costandi

I have completed several loans/refis with Mireille over the past 20 years. I wouldn’t work with anyone else.
Aug 24, 2021

Ken Moll recommends Ken Dean

This is the second property we’ve financed through Ken Dean. Both times were excellent, but the second time was even easier as he already had most all of our information, so providing a few updates was a snap. Despite his being busy, there was never a time we couldn’t reach him or he wasn’t quick to respond to an email inquiry. Thanks Ken. Job exceedingly well done!!
Aug 23, 2021

Cynthia Salinas recommends James W. Argo

Jim Argo and his Team are amazing. Courteous, thorough and communicative. I felt they gave us great frequent updates and Jim was always cool under pressure and in the current market - pandemic, low rates, etc - that is saying a lot. Jim even answered emails when on vacation in Europe which was very thoughtful. Professional all around and I would recommend him to friends/family.
Aug 20, 2021

Spencer R. recommends Joel Marks

Best customer service I have experienced in the last 20 years! Joel did what he said he would and did it on time!
Aug 14, 2021

Chuck Russell recommends Aisling Ferguson

Executive Director

Aisling gets the job done in record time. My realtor told me that no one ever managed to close a loan so quickly as Aisling. She takes the hassle out of buying or refinancing a home. I wouldn't consider a different broker.
Aug 13, 2021

Ellinor R. recommends Joel Marks

Joel Marks is one of the best in the business. Efficient, punctual and friendly, he did his best to get us a great rate, I will be using him for all our future loans!
Aug 12, 2021

Geoffrey Stott recommends Ken Dean

Ken did a great job for us on a commercial and residential refinance. Ken was always very communicative, reachable and accurate. We have worked with Ken a few times before and will love to do so again!

Our Team

  • Aisling Ferguson

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

  • Orlando Diaz

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

  • Kathy Derangi

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

  • James W. Argo

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

  • Larry Horowitz

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

  • Ken Dean

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

  • Robin Patronik

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

  • Pov Oum

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

  • Joel Marks

    Loan Advisor (NMLS: #216888/1850)

  • Kevin Casey

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

  • Allan McAllister

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

  • Cecelia Tyeskey

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

  • Mireille Costandi

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

  • Ming Leong

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

  • KC Murphy

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

  • Risa J. Meyer

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

  • Sheila Wood

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

  • Bob Siefert

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

  • Amy Lai

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

  • Mark Wiener

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