Companies have issued record amounts yen-denominated debt this year, as Japanese investors have looked to stock their portfolios with bonds not tied to their own economy and foreign banks have sought to capitalise on this.

About $20.6bn has been raised through 29 so-called Samurai bonds so far this year, an 80% increase from the $11.5bn raised via 19 issuances during the comparable 2010 period, according to data provider Dealogic.