Ethereum execution client Geth has seen its market share fall after community members raised concerns over the network’s diversity, fearing Geth’s concentration could lead to a “black swan event.”

On Jan. 23, Geth’s market share of the Ethereum network execution clients fell 5.2% to 78.8% after reaching 84% the day prior.

Geth is critical in handling transactions and executing smart contracts on Ethereum, but its preference among Ethereum validators has led to an imbalance in execution client diversity on Ethereum, sparking centralization concerns.

Percentage share of Ethereum network execution clients. Source: Clientdiversity.org

Ethereum decentralization advocates, including the founding member of the ETHStaker Community, known as “Superphiz,” stressed in a Jan. 24 X post that a bug in Geth could lead to a more than 80% wipeout of Ether ( ETH ) staked on the network.

“I’m not trying to convince you that every execution client is as robust or as mature as Geth. I’m just telling you that it’s a good idea to use less robust clients to prevent a black swan event,” he explained in another post .

Lachlan Feeney, founder and CEO of Ethereum infrastructure firm Labrys, suggested in a Jan. 23 blog post that Ethereum validators could risk losing everything.

“Staked ETH is not risk-free yield. Would you invest a minimum of $75,000 USD into an instrument where the maximum potential gain is 3.5% p.a. but the potential for loss is 100%?”

“Probably not, but this is what 84% of the Ethereum stakers are doing today,” Feeney added.

As Geth’s current share exceeds 2/3rds (or 66%), Feeney said a critical bug would “instantly stop the chain from finalizing.”

In that scenario, Geth validators that go offline would be subject to an “inactivity leak,” which results in the burning of their staked Ether until the execution recalibrates to a 1/3rd (or 33.3%) share of the network.

Feeney said 90% of a validator’s staked Ether could be wiped within roughly 40 days.

“Comparatively, a validator taken offline due to a minority client bug that does not stop the chain from finalizing would lose just 0.4% of its stake in 40 days.”

However, Feeney told Cointelegraph there would be a "very small window” for validators to exit and limit their losses as there is a rate-limited queue for how many validators can exit per epoch.

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Nethermind, the second largest execution client, increased its share from around 8% to 14% on Jan. 23.

Nethermind’s increased uptake came despite it identifying and fixing a critical bug in several versions of its execution client that caused users to fail to process blocks on Ethereum two days earlier.

The exchange explained Geth was the only Ethereum execution client that met its technical requirements since it started Ethereum staking in 2020.

“However, the tide is turning,” said Coinbase.

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