"Don't worry about a property downturn. We want to grow our investments from R10bn to as much as 10% of our R720bn investment capital over the next few years. So there's no downside for property investors." That, in effect, was the message from Public Investment Corp (PIC) CEO Brian Molefe, in a parliamentary briefing last week.

It's a theme that puts him in famous company. First it was the Alan Greenspan "put". After the 2000 market crash, the then US Federal Reserve chairman as much as said: "Don't worry about recession. I'll keep interest rates so low, they'll keep the property bubble going for years, avoid deflation and underwrite the US economy."

(In deal-making terminology, a put option is the right that the writer of a deal - and often the seller of an asset - gives the buyer of an asset to sell it to the writer at a given price. This happens in listed share deals when the price drops below a certain level, creating a floor price and minimising the buyer's risk.)

In the past few weeks we had the Ben Bernanke "put". The current Fed chairman in effect told the market: "I'll drop interest rates, and I'll pour as much as you need into the market to eliminate the liquidity squeeze."

Now it's the Molefe "put". The PIC must spend another R60bn to bring its property holdings to around 10% of R720bn in investment funds. That's 70% of the market capitalisation of the listed property sector.

Molefe and his investment team are willing to outbid competitors for stock. The PIC bought listed fund CBS earlier this year at R12/share, on a forward yield of 6,4%. This shocked the market and its main competitor, listed loan stock company Redefine, which thought it had CBS in the bag at a keen price R10,70 and 7,3%.

Macquarie First South property analyst Leon Allison says "the PIC doesn't have to worry about short-term dilution. It can take a very long view."

Catalyst fund managers' Paul Duncan says he and other fund managers were happy to sell CBS to the PIC, because they could immediately place the money in better-quality stock at higher yields. This implies that the PIC overpaid - but as a pension fund it can take a long view.

The PIC also has 10% of Acucap, 25% of SA Corporate Property and a fair slice of Growthpoint, giving it a 5% share of the listed property sector.

But it's also buying up unlisted properties. According to investors like Rupert Hackwill, who sold his Griffin Hackwill fund to the PIC for R844m, its people were pleasant to do business with, compared with the tough negotiators in the rest of the sector. "They didn't quibble about detail or try the usual tricks like adding their management fees to costs to bring down the price," says Hackwill.

But initial excitement at the PIC's involvement is giving way to wariness. "Fund managers are finding it more difficult to place money in a tightening sector, so they are less eager to take the PIC's cash," says Duncan. He feels the PIC is an influence, "but not the main driver. Foreign buying and fundamentals will also underpin the market."

But analyst Ian Anderson says the PIC "is too big for the property market. The signals I'm getting are that the PIC aims to build its holdings in the listed sector from 5% to 20% in the near term. It won't be irresponsible; it will buy on weakness. But that will be enough to distort the market by reducing investment opportunities."

Demand already exceeds supply in the sector, and demand-driven valuing of property and shares will inevitably lead to a bubble, followed some day by a crash. But this would not concern the PIC too much: it is interested in the income over 20 or 30 years.

"Clearly the message is that the property sector is too small and must grow," says Anderson. "But that will take time. Meanwhile the PIC should extend its mandate to buy property internationally."