A total of 1.3 million bitcoin (BTC) worth almost $9 billion was moved on-chain in a single hour yesterday. Despite this, the price of bitcoin is currently holding steady at around $7,300, after briefly spiking to more than $7,500 yesterday.

According to Rafael Schultze-Kraft, cofounder of on-chain market intelligence firm Glassnode, this is the highest hourly USD transaction volume in bitcoin's history. But who was moving so much bitcoin around? And why?

Glassnode said that this recent spike was largely caused by crypto exchange Bittrex, which moved around 1.18 million bitcoin ($8.7 billion) across a series of 21 transactions, each comprised of around 56,000 bitcoin. The move comes during Bittrex's scheduled maintenance, which will see the exchange upgraded throughout December 05, 2019.

Each of these transactions had a fee of around 0.00008 BTC, or around $0.60, this means Bittrex was able to move almost $9 billion for under $12.50.

As it stands, it remains unclear why Bittrex moved almost $9 billion in bitcoin, but some have speculated that the exchange may be upgrading its cold storage. Such significant movements have been associated with cold storage transfers in the past, with Binance moving around $1 billion in bitcoin into cold storage back in July.

Normally such a large transfer to an exchange would be considered a bearish signal, since this could lead to increased sell pressure. Conversely, large troves of bitcoin moving away from exchanges is typically seen as bullish, since this indicates a reduced supply. (The price of a coin is largely influenced by supply and demand). However, since this is simply an internal transfer, it is unlikely to significantly affect the bitcoin price action.