Building a hospital wing for pediatric AIDS patients. Supporting research to preserve the polar bear's habitat. Establishing an endowment at the student newspaper that gave you your start. For the philanthropic, giving back can be a beautiful thing.

Reducing your taxes is a beautiful thing too.

For high-income taxpayers seeking to shelter income, philanthropy can be the gift that keeps on giving. Instead of writing checks, though, savvy investors are signing over appreciated securities.

In the process, they're reaping double tax breaks—one for the current value of the securities, and again by avoiding capital-gains tax on the appreciation.

In some cases, donors are also getting paid for their generosity, through a charitable gift annuity or charitable trust. These two staples of the "planned-giving" repertoire give benefactors a fixed income over their lifetime as well as the immediate benefits of both capital gains and charitable tax deductions.

(A caveat: The securities must be held by the donor for a minimum of one year to qualify. At the individual's death, the charity or institution applies the gift according to the donor's instructions.)

Other philanthropic strategies—foundations, trusts, and hugely popular donor-advised funds—offer the same tax benefits, but don't generate income for the donor.

At the U.J.A. Federation of New York, 60 to 70 percent of the total dollars it receives as planned giving comes to the organization as appreciated securities from major donors, William Samers, vice president for planned giving and endowments, says.

"You'll see more planned gifts in a market like this," he says. "Whether it's the high-net-worth individual concerned about another Bear Stearns, I don't know. After the internet bubble, people rushed to lock in gains. It's the same now."

Surprisingly, many investors who engage in charitable giving—as much as 45 percent, according to some research—don't realize that multiple tax breaks are available to them, Kimberley Wright-Violich, president of Schwab Charitable in San Francisco, says.

An October 2007 study by Fidelity Investments found an even greater percentage—more than two-thirds of the individuals surveyed—weren't aware of the additional tax advantages of donating appreciated securities.

Another big slice—39 percent—didn't realize that they could hold onto fast-growing stocks and reap a tax benefit by repurchasing shares after donating them. That locks in a higher cost basis and avoids capital-gains tax on the appreciation.

Another 17 percent of respondents to the Fidelity survey didn't understand the tax benefits of donating appreciated securities at all, while 10 percent didn't know you could use appreciated securities to fund philanthropy.

Nor do most potential donors consider the nuances involved with small, local charities that can affect their giving, Wright-Violich adds. Many of these groups don't have their own brokerage accounts, for example.

Donor-advised funds offered by Schwab, Vanguard, and Fidelity, among others, solve many of these problems, Wright-Violich says. They offer flexibility, ease of entry and execution, and the knowledge that "you're not committing to something for a lifetime."