Quoted from this tweet
https://twitter.com/bittrexexchange/status/888880704393588736?lang=enyeah they accept wire transfers
If you are looking to fund your Bittrex account with USD, we support wire transfers and conversion to $BTC, $ETH, and $USDT
To get funding instruction
Is minimum
$10,000 USD YES
Looks like they are only looking for big whales and corporate clients for now.