(Dow Jones) Adviser Mitch Silberman's client was worth about $5 million and, at age 62, thinking about retirement.

She knew her portfolio was over-concentrated in equities. What's more, her stock holdings consisted almost entirely of her employer's shares.

Silberman, who is president and CEO of Silberman Wealth Management in Westlake Village, Calif., had something of a specialty in working with people in her situation: female scientists who built accomplished careers at biotechnology giant Amgen. Almost uniformly, they ended up with concentrated portfolios of highly appreciated Amgen stock.

"These women had paid a pound of flesh for their stock options," Silberman says. "They're very conservative, humble and frugal; they tend to spend a lot less than they make."

In short order, Silberman referred her to an accountant and an estate attorney, then convened a joint meeting with the client and all three professionals. It didn't take long for the group to agree that her over-concentration exposed her to significant risk. Trouble was, selling the company stock and distributing the proceeds from her 401(k) would result in an enormous tax hit.

Silberman proposed that the client take advantage of net unrealized appreciation rules, which allow individuals to transfer shares of company stock from a 401(k) to a taxable account and pay income tax only on the original cost basis-not on the shares' current value. When she sells the shares, she pays the long-term capital gains rate, and not the higher ordinary income tax rate, on the appreciation.

"This client ended up paying taxes of 15% on most of the shares' value, rather than the combined 40% state and federal tax she would have owed," says Silberman. "Both she and the CPA loved the idea."

Silberman then recommended the client put $1 million of the Amgen shares in a charitable remainder trust, which would sell them and reinvest the proceeds. She would take a 5% annual payout from the trust to support her living expenses, and would gain a large tax write-off. Upon her death, the funds remaining in the trust would be distributed among four charities she had selected.

He then set about crafting a portfolio that could produce income for living expenses while protecting the client's capital.

Silberman likes to combine marketable securities with nontrading assets to manage risks. When market participants panic, he contends, the nontrading assets are more likely retain their value. So in addition to investing through separate accounts, he put 20% of the client's portfolio in some relatively illiquid REITs.