(Reuters) - Investors have plowed money into funds tracking bitcoin, betting on a return of Republican Donald Trump to the White House even as they expect wild price swings in the world's largest cryptocurrency during the election week, data showed.

Exchange-traded funds (ETF) tracking the spot price of bitcoin notched net inflows of $917.2 million on Wednesday, the biggest one-day increase since March, according to the Block, a data and news provider.

BlackRock's iShares Bitcoin Trust ETF, the largest spot bitcoin fund by assets under management, pulled in $872 million in net flows, the largest one-day haul since its launch in January.

Bitcoin soared around 12% in October in anticipation of a second presidential term for Trump, who has styled himself as a pro-crypto candidate.

"The rising odds of a Republican sweep (has) fueled optimism for potential crypto-friendly legislation in Congress post-election," analysts at Ryze Labs said.

Polls show Trump in a neck-and-neck race with Democrat Kamala Harris, though betting sites such as Polymarket are pricing in much greater odds of a Trump victory.

Given the uncertainty, futures markets show investors are bracing for a volatile election week. Forward-implied volatility data from crypto derivatives exchange Deribit points to potential daily price swings of about 3.7% in bitcoin in either direction through Nov. 8.

Open interest on crypto derivatives exchanges - an indicator of market activity - hit an all-time high of $43.61 billion on Tuesday, as per data provider Coinglass.

The derivative activity, however, indicates traders expect volatility to subside and bitcoin to continue rising after the election week, said Luuk Strijers, CEO of Deribit.