A Mitt Romney presidential victory on Nov. 6 will spark a stock-market rally the day afterward, while a re-election of President Barack Obama will send stocks falling and send bonds gaining, said Bill Gross, founder and co-chief investment officer at fund giant Pimco.

"On Nov 7th a Romney victory good 4 stocks/bad 4 bonds. Obama vice versa," Gross wrote on Pimco's Twitter page.

"Long term not much difference. Structural headwinds dominate."

Editor's Note: Economist Unapologetically Calls Out Bernanke, Obama for Mishandling Economy. See What They Did

A Romney victory would generate applause from businesses expecting broader tax cuts and a dismantling of regulations such as the Dodd-Frank financial reform law or the president's Affordable Care Act, known widely as Obamacare.

An Obama victory would most likely allow the Federal Reserve to continue with its ultra-loose monetary policies.

Loose Fed policies have included commitments to keeping interest rates near zero for years to come.

Other measures include an ongoing program under which the Fed purchases mortgage-backed securities held by banks, a monetary policy tool known as quantitative easing that aims to drive down longer-term borrowing rates to encourage investing and hiring.

Side effects include a weaker dollar and rising inflation rates, which could affect longer-term bonds debt especially.

"Long-term bonds obviously are geared towards 10, 20 and 30 years out in terms of inflation. And we think at Pimco that that's really what the Fed is trying to do, promote at least 2 percent inflation and perhaps 3 percent inflation — and 3 percent inflation is not a long-term bond investor's friend," Gross told CNBC.

"Therefore, we would stick to two, three, four and five-year pieces of paper that basically are held down and held low in yield and supported in price by the Fed's efforts going forward," Gross added.

Quantitative easing, championed by the Fed under Obama, tends to send stock prices rising as well, though many experts feel the past rounds of stimulus have had all the effect they are going to have on equity indices.

Romney, meanwhile, has suggested that if elected, he would replace Fed Chairman Ben Bernanke after his term expires in January of 2014 with a more hawkish chairman.

That said, however, Republicans aren't always as hawkish toward inflation as they claim to be, Gross points out.

"Republicans have not really been — for the past 50 years at least — a tight-money party. Look at Nixon in terms of breaking the Gold Standard. Look at Reagan in terms of reappointing [Former Fed Chairman Paul] Volcker in 1984. Volcker was a Carter appointee and only reappointed when he was lowering interest rates," Gross said.

"Of course, Bush with Bernanke. So it's hard to find evidence that the Republican Party is really the party of tight money."

Meanwhile, the Fed decided at its October meeting to leave interest rates and policy stances unchanged.

"The Committee remains concerned that, without sufficient policy accommodation, economic growth might not be strong enough to generate sustained improvement in labor market conditions," the Federal Open Market Committee, the Fed's rate-setting body, said in a statement.

"If the outlook for the labor market does not improve substantially, the Committee will continue its purchases of agency mortgage-backed securities, undertake additional asset purchases and employ its other policy tools as appropriate until such improvement is achieved in a context of price stability."

Editor's Note: Economist Unapologetically Calls Out Bernanke, Obama for Mishandling Economy. See What They Did