Many investors appear to have shed their long-held hesitancy toward stocks and are now feeling excited about them.

“I think we’re seeing fear fatigue,” Darell Krasnoff, managing director at Bel Air Investment Advisors in Los Angeles, tells The Wall Street Journal.

As investors are pouring money into stock mutual funds and exchange-traded funds, they’re telling their financial advisers that they feel more comfortable buying stocks, and volatility is declining.

Editor's Note: The ‘Unthinkable’ Could Happen — Wall Street Journal. Prepare for Meltdown

The CBOE Volatility Index (VIX), which measures expected moves for the Standard & Poor’s 500 and is nicknamed the “fear index,” has stayed below 15 every day this year, the longest such streak since early 2007. The index traded above 20 a year ago.

“With individual investors’ allocation to stocks at 30-year lows, and stocks having been liquidated in favor of bonds for the last five years, there could be a long runway for money to return to stocks and drive prices higher,” Krasnoff says, adding that it’s still “very early” in the shift away from fear.

Large brokerage houses, such as Fidelity Investments and Charles Schwab, are reporting increases in customers’ trading activity.

The S&P 500 has risen for seven weeks in a row, the longest streak since January 2011. The index has risen 7.3 percent so far this year and hit a five-year high Tuesday.

“Even when the market goes down — which is when most of the volatility in the market tends to happen — those down days are quite modest,” Dean Curnutt, chief executive officer at Macro Risk Advisors, tells The Journal.

The recent wave of corporate mergers is adding to the bullishness of professional investors.

“More deals out there do create a good sentiment,” Kevin Divney, chief investment officer at Beaconcrest Capital Management, tells Bloomberg.

“CEOs now are looking further out, and that’s been the issue the past four years. If we can extend horizons it makes for better strategic decisions.”

In fact, approximately $40 billion in deals were announced in the United States on Feb. 14 alone, bringing the total for the month to more than $140 billion, Bloomberg noted. In the first two months of 2012, the total amount of deals was $99.6 billion.

Editor's Note: The ‘Unthinkable’ Could Happen — Wall Street Journal. Prepare for Meltdown