Financial services group SBI led bitcoin exchange Kraken's "multi-million dollar" series B round, which follows a $5m series A in 2014.

US-based bitcoin exchange Kraken has raised an undisclosed amount of funding in a series B round led by SBI Investment, the venture capital arm of financial services firm SBI Holdings.

Described only as a “multi-million dollar” investment, the terms of the deal remain undisclosed.

The virtual currency exchange claims to have been responsible for more than $1.4bn transactions since it was launched in 2011, trading bitcoin and other digital assets for euros, US and Canadian dollars, Japanese yen and British…