随着各公司忙着利用有史以来最低借贷成本的机会，全球的公司债热潮开始升温。

　　从全球巨头麦当劳（McDonald's Corp.）和金佰利（Kimberly-Clark Corp.）到印尼电信公司PT Indosat Tbk等都在忙着发行债券。

　　本月是有记录以来美国垃圾级公司发行债券最忙碌的一个七月。亚洲的债市今年有望创下纪录，欧洲公司也在飞快地筹集资金。

　　低借贷成本是一场前所未有的债市飙升的高潮，此次飙升始于2008年底、2009年初信贷危机最深重的时候，它一反各种预测，并没有很快失去势头。不过，个人投资者和专业投资者继续向债市投入资金，给了公司持续的资金流可以利用。

　　随着每一轮新的上扬，债市价格上涨，而与债券价格反向而动的利率则进一步下滑。如果经济升温、利率上升，大量买进债券的投资者将在债券价格下滑时受到严重打击。

　　不过，目前为止，很多令债券大涨的条件依然发挥著作用。美国联邦储备委员会（Fed）将短期利率定为近零水平，投资者对股市心存谨慎，经济前景过于低迷，难以引发一轮强劲的股市飙升，不过还没有糟到公司违约的地步。

　　无论大公司还是小公司都在利用低利率来提振资产负债表，接下来的几年有望节省数百万美元利息成本。公用事业公司Duke Energy Indiana财务主管德梅（Stephen De May）说，我认为，我们恰恰是在正确的时间开始进入市场，这是一个非常好的时机。该公司的子公司在7月初时发债五亿美元，利率为3.75%.据美国银行美林（Bank of America Merrill Lynch）的数据，这是有记录以来美国大型借款公司中第四低的利率。

　　本周，麦当劳发行了4.50亿美元10年期债券，收益率为3.5%，这是有记录以来美国借款公司发行的大规模债券中收益率最低的。5月份时，10年期美国国债的利率为3.5%以上。

　　据巴克莱资本（Barclays Capital）说，投资级公司债的利率最近平均只有4%，这是六年多来的最低水平，只比相对风险较小的国债高出1.7个百分点。

　　较低的借贷成本对公司利润是好事，而公司利润对整体经济和就业又会带来好处。Duke Energy Indiana用发行债券所得来为发电厂建设等项目提供资金。

　　不过，很多公司发债只是为原有的债务再融资。很多公司任由资金在资产负债表上搁着，以备未来发生新危机或增长放缓时之需。这意味着，借贷潮对经济带来的好处可能是有限的。

　　巴克莱资本Americas Investment Grade Syndicate负责人Justin D'Ercole说，他们并不是要投资，或是用资产来试图建立自己的业务。他帮助公司发行新债。

　　据数据提供商Dealogic的数据，今年截至目前，全球公司债的发行规模已达到约1.4万亿美元，较2009年同期创纪录的2.1万亿美元有所不及。不过，5月份和6月份的部分时间，债券发行基本暂停，原因是欧洲的主权债务危机愈演愈烈。

　　随着更多的投资者涌入债市，助推债券发行的热潮，随之增大的风险是他们只是在涌向最新的泡沫。观察人士质疑市场是否能继续产生这样的回报，猜测投资者是否为仍有风险的公司债支付了过高的价格。投资管理公司Thornburg Investment Management投资组合经理布雷迪（Jason Brady）说，我研究了麦当劳的债券，感觉就像连续吃了五个巨无霸。麦当劳是家优秀企业，不过我没必要为了区区3.5%的利率而冒着风险持有一家低A评级公司的债券。

　　The global corporate-bond boom is gathering steam as companies rush to take advantage of some of the lowest borrowing costs in history.

　　Companies from global giants McDonald's Corp. and Kimberly-Clark Corp. to Indonesian telecommunications company PT Indosat Tbk are rushing to sell debt.

　　This month has been the busiest July on record for sales by U.S. companies with junk-credit ratings. Asia's debt market is on pace for a record year，and European companies are also raising money apace.

　　The low borrowing costs are the culmination of an unprecedented bond-market rally that began in the depths of the credit crisis in late 2008 and early 2009 and has defied every prediction that it would soon run out of steam. But individual and professional investors continue to plow money into the bond market，giving companies a constant source of funds to tap.

　　With each new leg higher，the bond market gets more expensive and interest rates，which move in the opposite direction of price，fall even lower. If the economy heats up and rates rise，investors gobbling up bonds will get burned as bond prices fall.

　　But for now，many of the conditions that got bonds rolling in the first place still hold sway. The Federal Reserve has short-term interest rates near zero，investors are leery of stocks，and the economic outlook is too sluggish to spark a robust stock boom but not so bad that it causes companies to default.

　　Companies big and small are taking advantage of the low rates to bolster their balance sheets and lower their interest costs by millions of dollars for years to come. 'I think we are accessing the market at precisely the right time， and a very opportune time，' said Stephen De May，treasurer of Duke Energy Indiana，whose subsidiary in early July borrowed $500 million at 3.75%，the fourth-lowest rate on record for a large U.S. corporate borrower，according to Bank of America Merrill Lynch.

　　McDonald's this week raised $450 million in 10-year debt at 3.5%，a record low yield for a large batch of debt issued by a U.S. corporate borrower. The U.S. government paid more than 3.5% for its 10-year debt as recently as May.

　　Interest rates on investment-grade corporate bonds recently averaged just 4%，according to Barclays Capital， the lowest in more than six years，and just 1.7 percentage points above relatively risk-free Treasury debt.

　　Lower borrowing costs are a boon to corporate profits，which could in turn benefit the broader economy and hiring. Duke Energy Indiana used its debt proceeds to fund power plant construction among other things.

　　But many companies are simply borrowing to refinance old debt. And many are leaving the cash haul on their balance sheets，bracing for the possibility of fresh crises or leaner growth ahead. That suggests the economic benefit of the borrowing boom could be limited.

　　'They're not looking to invest or to take on assets to try and build their business，' said Justin D'Ercole，head of Americas Investment Grade Syndicate at Barclays Capital， who helps companies sell new debt.

　　Corporate bond sales around the world so far have reached about $1.4 trillion this year， lagging behind the record $2.1 trillion for the same period in 2009， according to data provider Dealogic. But offerings were largely put on hold during May and part of June as the sovereign-debt crisis grew in Europe.

　　As more investors pour into the bond markets —— helping fuel the debt sale bonanza —— the risks increase they are just hopping on the latest bubble. Observers question whether the market can continue to generate such returns and wonder if investors are paying too dearly for corporate bonds that still have risks. 'I looked at McDonald's debt and felt marginally the same as if I'd eaten five Big Macs in a row，' said Jason Brady， portfolio manager at Thornburg Investment Management in Santa Fe. 'It's a great company，but I don't need to own a low-A-rated corporate risk at 3.5%.'