Bitcoin (BTC) miner Marathon Digital (MARA) will stash some of its digital assets with Fidelity Digital Asset, adding a second custody partner in an attempt to diversify.

"Historically, Marathon has custodied all its bitcoin with a single provider," Marathon said in a statement Wednesday. "As part of its broader treasury management strategy," the company added, it has "added a new, enterprise-grade custodian as its second custodian."

In a separate filing, the miner said it would open one or more custodial asset accounts with Fidelity.

Marathon said it may expand even further and add more custodians. The company had 13,726 bitcoin as of Sept. 30 and it's producing over 1,000 more per month, so "we believe it is an opportune time to diversify our bitcoin custody across multiple custodians," Marathon CFO Salman Khan said in the statement.

Custody plays a key role in crypto and other markets. Firms that don't want to store their own digital assets like BTC can entrust them with a third party. Having more than one company doing that ensures that if a single provider runs into trouble, at least all of your assets won't be lost.

Marathan's decision comes after several custodians, including Fortress Trust, have been targeted by hackers that stole some digital assets. In the case of Fortress Trust, the theft spurred the custodian to try to sell itself to blockchain tech company Ripple, but that deal fell apart.

The miner's stock was up 1.3% in post-market trading. It has risen 116% this year, while bitcoin has climbed 71%.