Millennials' stock market aversion is a momentum-driven trend that may be accelerating with Bernie Sanders' anti-Wall Street messaging, and it isn't unfounded.

Many millennials were just getting started in the workforce in 2008. Their first exposure to the stock market was through 401(k)s, and some quickly lost up to half their plan money in stock-heavy default investment choices.

Now, many complain that the stock market feels rigged to favor insiders, which also isn't unfounded, given unchecked high frequency trading.

So, how should you try to cultivate millennial as clients? And if you believe they eventually will need some stock market participation to achieve financial goals, how can you convince them to give the market a try?

Let's start with a logical premise: Millennials who aren't yet in the stock market are most likely to participate through their 401(k)s and other participant-directed workplace plans. The problem is that they feel pressured to choose (or default to) a stock-heavy investment choice or plan.

The best way to gain their attention and win their trust is to offer education and counseling that focuses on these actions:

• Using payroll deduction and retirement plan tax advantages to create a systematic savings habit.

• Steadily increasing personal contributions or deferrals over time.

• Taking advantage of matching contributions from employers and the federal government (Saver's Credit).

• Understanding all plan investment options, starting with the most conservative.

• Creating an asset allocation plan and making active investment choices – not automatically accepting a stock-heavy (target-date) default choice.

• Beginning to diversify into equities when their plan balances have accumulated to a goal amount, such as $20,000.

You also can emphasize other financial services that appeal to millennials, including life and disability income insurance, long-term care insurance, financial planning, and credit management.

Most experienced financial advisors believe some stock market participation is essential to achieving lifetime financial goals. Whether or not this idea is valid, recognize that it can be a turn-off for millennials.

Also, you may want to consider how strong the stock market of the future can be unless advisors help millennials address and overcome their concerns, little by little. If you want to build relationships with them, speak their language and appeal to their values. Like Bernie!