Private equity firms have stopped betting the house

Don't let those headlines fool you, the private-equity industry's days of big leveraged buyouts are behind it.

The headline recently was a massive takeover of EMC by Dell. The $67 billion bid was backed by Silver Lake Capital, Michael Dell and Singapore investment fund Temasek.

Dell's borrowing heavily to fund the deal, but its not classified as a leveraged buyout because the primary buyer is a company and not a fund.

Similarly, when H.J. Heinz said it would acquire Kraft Foods in March, the fact that it had alot of help from 3G Capital and Berkshire Hathaway wasn't enough to make the deal a buyout.

And so, the pure-LBO drought continues. A number of factors have hampered big deals in the wake of the financial crisis. Loans for big deals were scarce in the wake of the market plummet and big investors were licking their wounds - and struggling to figure out how to mark their existing deals to market.

Later, tough guidelines for big banks that were issued by the Federal Reserve and Treasury Department held big buyers out of big deals. The LBOs that are taking place are less reliant on debt, Fitch Ratings says. Through September, LBO-loan issuance reached $57 billion. Compare that with $207 billion in 2007.

In fact, it took until 2013 for a big buyout to be completed that cracked the top 15 in M&A rankings. That was the $25 billion buyout of Dell by the company's founder and Silver Lake.

The biggest LBO of 2014 was the $8.7 billion buyout of retailer PetSmart by UK investor BC Partners. In 2015, no buyout has matched its' size. Coming close in 2015 was the $8 billion buyout of software firm Veritas from Symantec by Carlyle Group and Singapore wealth fund GIC.

Here's a list of the biggest deals of all time, with rankings adjusted for inflation.