A large investor tapped an ETF tracking high-yield corporate debt to conceal his trades and acquire about $780 million of bonds, according to a report.

The unnamed investor last Thursday exchanged nearly 20 million shares of SPDR Barclays Capital High Yield Bond ETF (NYSEArca: JNK) for $779.3 million in bonds held by the fund, Bloomberg News reported.

“The redemption, the biggest in the four-year history of the $11.4 billion fund, came after the investor had accumulated shares over several weeks, according to Knight Capital Group Inc., which brokered the trade,” the story said. “The investment in the fund, which tracks the Barclays Capital High Yield Very Liquid Bond Index, may mark a new way for investors to gain control over a large group of bonds without tipping off other investors.”

ETFtrends reported on the volume spike in JNK on May 10. [High-Yield Bond ETF Volume Surges]