Investors tired of miniscule returns from their money market accounts and intrigued by small-cap funds in a variety of industries pumped more than $11.3 billion into diversified U.S. equity mutual funds in the first quarter and more than $14.8 billion into global sector funds.

This spike in mutual fund inflows was especially pronounced among small-cap funds, according to data S&P obtained from Lipper, as all three small-cap peer groups garnered inflows in excess of $1 billion in the first three months of the year with small-cap core and small-cap growth funds receiving inflows of $3.6 billion and $1.6 billion, respectively.

Meanwhile, large-cap core funds and large-cap value funds took a hit over this same period, losing $8.8 billion and $1.1 billion, respectively, in capital as investors continued to favor so-called "risk on" trades in the belief that these smaller firms' earnings will outpace the expected growth of their larger brethren.

But this recent infatuation for small-cap funds will likely reverse itself, according to S&P's equity research analysts, as the current economic cycle matures and large-cap funds become more compelling and competitive.

"As we go further into the third year of this bull market as the economy continues to recover, historically we've seen that large-cap stocks and funds do better," said S&P mutual fund analyst Todd Rosenbluth. "As a bull market matures, more stable companies benefit more. If we see gains in large-cap stocks, which we think we'll see, we'll see more money flow back into these large-cap funds."

Rosenbluth said the strong performance of many small-cap growth and small-cap core funds is owed largely to investors -- new and old -- putting their money into stocks and mutual funds that have performed best most recently.

"Part of this growth is not necessarily for the right reasons," he said. "When investors are looking to put money into the market, they're often following the trend and what worked in 2010, in many cases, were these small-cap stocks and funds. However, these small-cap stocks are more volatile than large-caps so as someone much smarter than me once said, the trend is your friend until it isn't."

By sector, commodity and natural resource funds enjoyed inflows of more than $6.2 billion and $3.7 billion, respectively, in the first quarter as oil prices continued to spike and investors hedged against looming inflation concerns by pushing gold to an all-time high of $1,500 an ounce.

In its "Trends & Ideas" missive, S&P this recommended a number of its five-star funds from these sectors including Fidelity Small Cap Discovery Fund, Franklin Natural Resources Fund A, Guinness Atkinson Global Energy Fund and T. Rowe Price Small-Cap Stock Fund.

Mutual funds, ETFs, 401(k)s and individual retirement accounts have all enjoyed strong recoveries and inflows in the past year. In the fourth quarter, total retirement investment assets surged to more than $17.5 trillion, up 9.1% for the year.