(Bloomberg) -- The world’s biggest asset manager is leaning into the stock market’s post-election rally after shying away from risk exposure in the run-up to the vote. 

More than $1.9 billion flooded into the $13 billion iShares MSCI USA Momentum Factor ETF (ticker MTUM) on Friday, the biggest one-day flow since the fund’s 2013 launch, data compiled by Bloomberg show. At the same time, a record $1 billion exited from the $32.5 billion iShares Core Total USD Bond Market ETF (IUSB). A BlackRock spokesperson confirmed that the firm adjusted its model portfolio allocations last week. 

The influx of funds into MTUM reflects BlackRock’s conviction that US equities — fresh off their best weekly performance of 2024 — will continue to climb as a “coiled spring” of pent-up business activity unwinds. With election uncertainty resolved, decisions on corporate capital allocations that were formerly on hold will resume. As such, the firm’s model portfolio team, which oversees about $131 billion in assets, is increasing its overweight on stocks from 3% to 4% heading into year-end.

“Rather than attempting to thread the needle with tactical sector or industry bets tied to specific electoral outcomes, we’re positioning for a broader relief rally that we believe will transcend partisan results,” Michael Gates, lead portfolio manager for BlackRock’s Target Allocation ETF model portfolio suite wrote in investment commentary dated Nov. 8. “This ‘uncertainty discount’ embedded in market prices should begin to thaw as businesses and investors regain their footing and seek to execute on delayed strategic initiatives.”

Model portfolios — which package together funds into ready-made strategies to sell to advisers — have ballooned in size in recent years. Broadridge Financial Solutions estimates that model assets likely reached $5.1 trillion at the end of 2023, and could reach $11 trillion by 2028. As a result, even small adjustments can cause big shifts in ETF flows. 

In addition to post-vote clarity, Gates wrote that recent economic data — showing that the labor market is cooling while growth remains resilient — should support the Federal Reserve’s rate-cutting campaign, adding to the firm’s bullish conviction. 

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