Recent studies have examined how companies in the Standard & Poor's 500 index have fared over the past half-century when taxes on dividends change. They found dividend-paying stocks performing in seemingly unpredictable ways.
Between 1990 and 1993, for example, when dividend taxes climbed to a maximum of 39.6 percent from a maximum of 28 percent, dividend-paying stocks outperformed the broader market.
"The 'fiscal cliff' will be a big deal for the stock market if it's not avoided," says Russ Koesterich, global chief investment strategist for BlackRock's iShares group. "But it's probably not such a big deal for many dividend-yielding stocks."
Tax increases and government spending cuts known collectively as the "fiscal cliff" are set to take effect Jan. 1 unless Congress and President Obama reach a deal first.
Obama wants to keep the tax cuts in place, including the 15 percent dividend rate, for people making less than $200,000. Republicans want to keep the tax cuts for everyone, including the 15 percent dividend rate, but have not taken a hard line on the dividend rate publicly.
Dividend payments were taxed like everyday income, meaning taxed by increasing brackets, until 2003, when Congress passed sweeping tax cuts backed by President George W. Bush.
The 2003 cuts reduced the tax on most dividends to 15 percent.
If Obama and Congress can't make a deal, and perhaps even if they can, dividends will be taxed like everyday income again. And the top marginal income tax rate will climb back to 39.6 percent from 35 percent, where it has stood since 2003.
The country's top earners will be taxed an additional 3.8 percent on dividends to pay for the president's health-care overhaul, meaning that the wealthy will pay 43.4 percent on dividends - almost triple the tax they pay today.
For millions of Americans, a dividend tax increase won't matter. Stocks in most individual retirement accounts and 401(k)s will be unaffected until years from now, when the account holders cash them in.
Fidelity Investments estimated two years ago that a third of U.S. stocks are held in tax-deferred accounts IRAs and 401(k)s. Another 13 percent are held by foreigners, who don't pay U.S. dividend taxes.
It's tricky to make any historical comparisons because nothing like this has happened before. There has never been such a large increase on dividend taxes, partly because they have generally gone down.
The closest historical parallel is probably the early 1990s, says David McGonigle, a fund manager at Copeland Capital Management. The top income-tax rate rose from 28 percent to 31 percent in 1991, then climbed to 39.6 percent in 1993.
So did higher taxes prompt investors to ditch dividend stocks? Not at all. Between 1990 and 1993, dividend-paying stocks returned an average of 12 percent a year. The S&P 500 returned an average of 10.7 percent.