Financial planning and beyond

By understanding what’s most important to you, we can organize your financial life to help make sure your short-term needs don't cloud your long-term goals. We provide a structure so you clearly understand where your money is, and why. The plan we create together can help you stay focused at each stage of life, today, tomorrow and for future generations.

Chess board

William S. Costas

Vice President–Wealth Management

The focus of our relationship.

My passion is wealth management; I take a goals based approach to assist my clients in embracing their future by providing insight and perspective, no matter how complex the situation. By leveraging our firm's extensive global resources coupled with industry leading insight, I will construct a tailored strategy designed to achieve the goals that are most important to you.


W. Stephen Costas Vice President--Wealth Mgmt

I began my career with Merrill Lynch three months before one of the equity market’s most tumultuous months on record – October 1987. I then joined UBS in 1991 as Assistant Vice President Municipal Bond Trader before becoming a Financial Advisor in April of 1994.Over the past 20 years I have provided unparalleled support to clients in managing their wealth through ever-changing conditions.

With my clients I place an emphasis on asset allocation and total portfolio management; while taking a holistic approach to retirement income planning and wealth preservation. I am also equipped to give guidance on funding education, structures for charitable giving and estate planning.

I am FINRA-registered and hold Series 7 and 63 securities licenses. I obtained my bachelor’s degree is in finance from Miami University and my M.B.A. from UCLA.

I raised my three children Emily, Nicholas and Hailey in Westlake Village, CA and I now reside in Oak Park, CA with my wife Tami and our German Shepard Nico.

Registered States:
  • AZ
  • CA
  • CO
  • DC
  • HI
  • ID
  • IL
  • IN
  • MO
  • NJ
  • NV
  • NY
  • OH
  • PA
  • VA
  • WA


  • B.A. in Finance, Miami University
  • M.B.A. in Business Administration, UCLA
3011 Townsgate Road
Suite 300, 3rd Floor
Westlake Village, CA 91361
  • (805) 367-3640

Email Me

Why does A.I. in space matter?

Outlook on interest rates


UBS and Credit Suisse—stronger than ever

Global Wealth Report 2024

Crafted wealth intelligence

Now in its 15th edition, the Global Wealth Report 2024 offers you leading insights into household wealth and prosperity across the world. In the US, average wealth growth has spiked from 3.7% between 2000 and 2010 to nearly 6.3% between 2010 and 2023.

Gain additional insights into the trends shaping wealth in the US and around the world.

Download the report

A leader in wealth management

Backed by the strength of our parent company, UBS AG

$5.8+ trn

UBS Group invested assets
As of 03/31/2024

51 countries

Our global footprint

Global leader

UBS is a leading and truly global wealth manager