Early on Wednesday, Apple 10-year securities yielded around 77 basis points above U.S. Treasurys, and market chatter focused on a possible euro-denominated issue in the near-future.
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Meanwhile, equity investors seemed to have rediscovered their love for Apple, with shares trading near $595 early Wednesday on Wall Street. (Click here for the latest quote.) Plus, Goldman Sachs raised its price target on the stock to $635 from $620 on Wednesday, a clear signal Apple may push U.S. markets higher this year.
But whereas equity investors have been cheered by dividend payments and an aggressive stock buyback program, fixed income players are left wanting more, according to Blain. He said Apple needed to prove it could innovate over the long-term.
"If I am going to buy a long credit: I want to know cash will be there when redemption day comes around," he said.
"If it was something like a railway line or a manufacturer, I'd probably accept long-dated debt by a well-run firm, on the basis it's a long-term business and the assets will be there in 10 to 30 years' time.
"In Apple's case, I have to look at the history of the sector. It's a fast moving rise-and-fall bear pit. The firms that led the world making tech stuff 20 years ago don't lead today."
—By CNBC's Matt Clinch