Piggy banks filled with money are displayed on a desk during a "Save our economy" campaign by Korea Saemaulundong Centre in Seoul. Reuters/Jo Yong Hak A handful of huge investors have been saving up.

Now everyone wants to know when they will start breaking in to their piggy banks.

The private equity giant KKR & Co. said Monday that it had a record-high $35 billion in dry powder, or money waiting to be spent, according to a letter to shareholders.

That $35 billion adds to a huge pile of cash sitting at its rival private equity funds Blackstone Group, Oaktree Capital, Carlyle Group, and Apollo Global Management.

Oaktree has "near record levels of dry powder shadow AUM," CEO Jay Wintrob said on a first-quarter earnings call, adding up to $21.4 billion, according to filings.

Carlyle has a $43 billion war chest, according to first-quarter results. Blackstone had amassed about $80 billion in untapped funds as of December, its annual filings show.

And Apollo, which will report first-quarter numbers on May 5, has an estimated $26 billion in dry powder, according to Credit Suisse analysts.

That puts the total figure for dry powder across the five firms beyond $200 billion.

This pile has been growing for some time, and the fact that it has been allowed to build says something about the industry's struggles to find bargains amid a volatile market, driven by impending interest-rate hikes, a slowdown in China, depressed commodity prices, and shaky leveraged credit markets.

It now has analysts asking when these firms will start spending that money and what they will spend it on. Most of the PE firms seem noncommittal.

Glenn Schorr, an analyst from Evercore ISI, asked Blackstone whether there was incentive for the private-equity firm to put the dry powder to work more quickly, for example.

Hamilton James, Blackstone's president and chief operating officer, said in response:

I don't think we're ... impatient investors. As I say, we wait till there's an interesting investment to draw down the money. It's not like we take the money and then it burns a hole in our pocket.

On Oaktree's first-quarter earnings call, Credit Suisse analyst Craig Siegenthaler asked about deployment in the first quarter and through the rest of the year. Bruce Karsh, cochairman and chief investment officer at Oaktree, said:

The window closed relatively quickly [in the first quarter], and we didn't get all that we had wanted when we were in the market looking for opportunities. But we felt that we did a reasonable job of putting money to work in Q1.

And with respect to the rest of the year, it's really going to be a function of what the environment is. We still think we're going to continue to deploy, although what we were doing in Q1 is probably not as much of what we're going to do in Q2 and beyond. We see some other opportunities outside of public US corporate debt that looks interesting to us. And, of course, the energy sector is still interesting.

Carlyle and KKR seemed a bit more positive about the prospects for deployment.

On Carlyle's first-quarter earnings call, CEO David Rubenstein said deployment had picked up since February:

In the first quarter, we closed approximately $3 billion of these transactions, and we remain confident that we will continue to find attractive opportunities to deploy our $43 billion of carry fund dry powder.

Scott Nuttall, head of KKR's global capital and asset-management group, described the first quarter as "strange" and "volatile" in a conference call on April 25:

The market was quite volatile in Q1. We find ourselves in a bit of an emotional market with a bias to negativity. And our job as investors is to monetize the emotion. And so when we've got volatility and things get cheaper, we're investing into that, and that's why you saw the deployment that you saw in the quarter.

And when the market gets happier again, we're selling into it and that's why you've seen the exits in the quarter both the strategics and secondaries into the market, and the refinancing that we've been doing when the market gets more upbeat as well.

If after reading all these comments you're still wondering when the firms will start splashing the cash, don't worry. We are too.