Just hours before the U.S. election got underway, investors pulled the most cash ever from the world’s largest exchange-traded fund tracking corporate bonds.

As market volatility awakens and the pandemic hits America Inc.’s creditworthiness, more than $1.4 billion exited the iShares iBoxx $ Investment Grade Corporate Bond ETF (LQD) on Monday, according to data compiled by Bloomberg. Trading activity included a single transaction worth about $250 million, though it’s unclear if that constituted selling or buying.

Given how much LQD has rallied in the months since the Federal Reserve’s credit-market backstop, there would be “solid reasons” to reduce long positions on the eve of the U.S. presidential vote, according to Mizuho International Plc.’s Peter Chatwell. Not only are corporate bonds vulnerable to a selloff should equity markets swoon, but LQD’s relatively high 10-year duration -- a measure of sensitivity to rate changes -- means the fund could suffer if a wave of risk-on sentiment boosts yields, he said.

“Most market focus ahead of the election has been on the downside risks to equities, but credit is almost as vulnerable,” said Chatwell, Mizuho’s head of multi-asset strategy. “Locking in some profit at this point makes plenty of sense.”

All in, the redemption dwarfs the previous record of $1.1 billion in late February when the coronavirus sparked widespread turmoil. Yet even without the election, LQD has been quietly getting more risky as rating downgrades and a boom in issuance take the number of BBB rated securities in the $54.7 billion fund toward a record.

Out of 2,321 holdings, the ETF had 1,150 bonds rated BBB at the end of October, data show. The hefty contingent underscores the need for investors to look under the hood of funds they choose, according to Bloomberg Intelligence’s James Seyffart. Rising infection rates and new lockdowns could spell trouble for at least some of these bonds.