Of all the funding raised for 2013 private equity (PE) buyouts, 50% went to the largest funds, based on data released by London-based research firm Preqin on Friday. Since 2008, it was the first time that megafunds have controlled half the market, according to The New York Times.

Preqin said of the $169 billion closed by 145 buyout funds in 2013, $85 billion were taken by megafunds, or those that hold more than $4.5 billion in assets. In 2012, $30 billion went to megafunds out of the $95 billion raised. That is about 30% of the total amount raised, the report detailed.

This change came about after overall fundraising activity resurged last year after being muted for several years. Investors are once again willing to invest large sums to buyout specialists. Preqin said the average PE fund last year was $1.2 billion, compared with 2012's $740 million and 2008's $1.1 billion, the report stated.

Apollo Global Management closed an $18.4 billion fund by the end of 2013. Investors also allowed the firm to raise the fund size cap of $15 billion. Because of this, the company raised the biggest PE fund in its history, the report stated.

Antone Drean, chairman of placement agent Triago, said size may not be the main reason for the success of megafunds in capital raising, the report said.

Drean explained: "It's really a question of performance and story. It's a question of being able to demonstrate that the money will be well managed. Whereas large managers may not be able to produce the highest returns, they are often a little more consistent. I think that's what investors are looking for."