NEW YORK, March 5 (Reuters) - The U.S. market regulator is more than quadrupling the transaction fees it charges exchanges -- which in turn pass them on to investors -- in response to plunging stock prices.

The Securities and Exchange Commission said on Wednesday that it would charge $25.70 per $1 million in securities sales, up from the current $5.60, for transactions on exchanges and the private over-the-counter markets. The new fees take effect in April.

The regulator said it needed to boost its take to reach the targeted collection amount of $1.02 billion in fiscal 2009. The current transaction fee is among the lowest the SEC has ever charged; the new fees are closer to previous years.

The SEC regularly makes midyear fee adjustments if it calculates its target will not be met.

U.S. stock markets have fallen to multiyear lows in recent months. Meanwhile, the SEC is probing an increasing number of high-profile and costly cases, including separate frauds allegedly committed by billionaires Bernard Madoff and Allen Stanford.

John Giesea, president and chief executive of the Securities Traders Association, said the increase was expected. “The emotional reaction is that this is not a shock to the system,” he said. (Reporting by Jonathan Spicer; Editing by Lisa Von Ahn)