The ominous “thud, thud, thud” of heavy envelopes will be hitting the doormats of UK investors over the next few weeks. It will be the sound of demands for cash – not from angry creditors, but from impoverished listed companies. Corporate UK has finally woken up to the fact that, with cash reserves dwindling and access to debt finance limited, it once again needs to ask its shareholders for more money.

In fact, UK companies have been launching fundraising initiatives at quite a rate. There are nine rights issues under way at the moment, along with two open offers. More are expected soon as the laggards get into gear. The 11 companies already doing the mail-outs are asking for more than £7bn – a tidy sum considering that their combined market capitalisation is only £14.5bn.

The largest number of begging letters comes from the property sector. Giants British Land and Land Securities are looking for £740m and £756m respectively, while Hammerson and Workspace are also seeking extra cash. The insurance sector is also well represented, with Beazley and Catlin going cap in hand. They’ve been joined by a smattering of other companies, including miner Xstrata, electronics manufacturer Cookson, telecoms operator Colt and building materials supplier Low & Bonar.

The fact that most of these companies have chosen to launch rights issues (which offer the same opportunity to all shareholders), rather than raise funds in other ways, is itself a sign of the times. During the boom years, share placings were all the rage. Favoured institutional shareholders were offered the chance to invest, while private investors were left out in the cold.

These days, though, companies are being more cautious. The institutions are getting uppity because they, too, have been left out on certain occasions. Witness the outrage that Barclays provoked when it raised money from Middle East investors last year. More recently, Rio Tinto has enraged its institutional shareholders by offering Chinalco convertible bonds on favourable terms. For companies hoping to raise a large sum of cash, a rights issue is clearly the more straightforward route.

So, after years of neglect, private shareholders are being offered the chance to invest on the same terms as the big boys. Should we accept? Are these companies deserving recipients of the cash that we have been holding back in recent months? Or should we refuse – concluding that it’s better to turn down new shares, allow our stakes in these businesses to be diluted, and let the underwriters take up the slack?

It’s a delicate issue. There are plenty of attractive discounts on the new shares being offered, particularly in the property sector. Shareholders in British Land are being given the chance to buy new shares at a 49 per cent discount to the current market price, while Land Securities is offering a 50 per cent discount. Xstrata’s 68 per cent discount looks enticing.

But going for the big discounts in the hope of a quick win is a dangerous game. It’s no coincidence that some of the biggest discounts come from the property sector, where plummeting asset values and frozen markets have left little scope for either debt financing or asset sales. New equity is therefore a must – and the large discounts show that the companies need investors far more than investors need their shares.

Elsewhere, there are narrower discounts on offer where the companies are telling growth stories rather than sob stories. The rights issues from Beazley and Catlin, together with a recent open offer from Chaucer, reflect a desire to profit from opportunities in the insurance market. With premium rates finally starting to rise after years of declines, insurers are rushing to repair their balance sheets so that they can write new business.

For me, this is a far more attractive scenario than the chance to put money into a declining property market. However, not everybody agrees. Writing in the Financial Times this week, Niall Paul, deputy chief executive of Aviva Investors London, pointed to data from the last recession suggesting that “in the two years following a rights issue, companies seeking funds to repair balance sheets outperformed the issues of companies searching for funds for future growth.”

That’s fine in theory, but I can’t share his optimism. Anyone who put money into the banks’ rights issues last year will know that investing in rescue situations is a dangerous business. There’s no upturn in sight for the property market. So increasing exposure to this ailing part of the economy does not (yet) form part of my asset allocation plans.

And that, really, is where any decision about investing in rights issues should start and end. It’s not a question of the discount on offer, or the risk of dilution. It’s a question of how much I need exposure to the company. Given the parlous state of many of the companies seeking cash, the answer has to be: not much.

Oliver Ralph is editor of Investors Chronicle