Money pours into stocks—does that signal a top?

Money pours into the market

As money surges into the market, is it time for savvy investors to cash out?

That's what a report from TrimTabs suggests, at least on a near-term basis. The investment research company reported on Sunday that investors have added $46.8 billion to equity mutual funds and exchange-traded funds in March, the most for any month since October 2013.

"Fund flows data does not bode well for U.S. equities in the short term," TrimTabs concludes.

Indeed, investors often take fund flows to be a contrarian indicator. The basic idea is that once everyone buys, there's less money left to go into the market. Additionally, heavy buying could be seen as a sign of investor exuberance, indicating that stocks are in "overbought" territory.

Indeed, TrimTabs adds that flows into and out of leveraged ETFs (which move twice or three times as quickly as the underlying set of stocks) are "also worryingly upbeat," with leveraged short ETFs redeeming assets for the second straight week, and leverage long ETFs issuing assets for the fourth straight week.

Read More Here's proof that the rising dollar is good for stocks

Still, not everyone finds the buying to be quite so worrisome.

"I don't think it signals a top of any sort. It's a lagging indicator. It's garbage, as far as I'm concerned," said David Seaburg, head of equity sales trading with Cowen & Co.

In fact, Seaburg says that many of the well-known indicators don't work in such a central-bank-dominated trading environment.

"The old sort of indications of what signaled the top in the past are out the window," he said. "Look how long it has taken us to get our arms around the volume. Markets that go up on low-volume days, does that mean it's not a confirmed sort of rally?"

The key now is "don't fight the Fed, and also don't fight every central bank out there keeping rates as low as they are," he said. "I think the market is going to grind higher."

Indeed, using fund flows as an indicator certainly wouldn't have worked the last time flows were this heavy. The is up 20 percent since in October 2013.

"You've got to know when to join the trend and when to fight the trend," said Todd Gordon of TradingAnalysis.com. "And right now, I think it's time to be part of the trend and ride the wave."