Earlier this month, Valve declared its intention to send shutdown notices to CS:GO skin betting websites that were improperly using the Steam API. According to Wykrhm Reddy, Valve has now named more than 20 sites which have been given 10 days to cease using their Steam subscriber accounts for commercial purposes.

Following gambling websites have been sent a cease and desist order due to violation of the Steam Subscbr Agreement. pic.twitter.com/zyqwcBPtpS — Wykrhm Reddy (@wykrhm) July 20, 2016

In total, the notice lists 27 gambling sites, including CSGODiamonds, CSGOLounge, CSGODouble and CSGOWild. It also includes Dota2Lounge, a Dota 2 gambling site. The list focuses on jackpot-style skin lottery sites, while pro match betting sites, like Unikrn, Betway and Gosubet, appear to be unaffected.

Earlier on Tuesday night, one of the sites on the list, CSGOBig, posted what it claims is a copy of the notice sent to them by Valve.

Hey guys, #CSGOBig will be disabling deposits and will be shutting down temporarily to comply with Valve. Read more: https://t.co/aDjhKNF65z — CSGOBig (@CSGOBig) July 20, 2016

The full text of the notice, which contains the same list of affect sites and appears to have been signed by Valve general counsel Karl Quackenbush, reads:

We are aware that you are operating one of the gambling sites listed below. You are using Steam accounts to conduct this business. Your use of Steam is subject to the terms of the Steam Subscriber Agreement ("SSA"). Under the SSA Steam and Steam services are licensed for personal, non-commercial use only. Your commercial use of Steam accounts is unlicensed and in violation of the SSA. You should immediately cease and desist further use of your Steam accounts for any commercial purpose. If you fail to do this within ten (10) days Valve will pursue all available remedies including without limitation terminating your accounts.

theScore esports has not yet been able to independently verify that the letter was distributed by Valve, however the language and terms are similar to those posted by Reddy.

CSGOBig says it has disabled new deposits and temporarily ceased operations to comply with the notice.

In a public statement given on Steam last Thursday, Valve's Erik Johnson said the company was aware that several CS:GO gambling sites were using automated steam accounts to acquire and trade skins as part of the lottery process. Johnson said this practice violated Steam's terms of service, and Valve would be taking action to ensure compliance.

Bryce Blum, an esports lawyer, wrote in an ESPN column this week that Johnson's statement did not explicitly forbid skin gambling, and said that the wording gave the sites the opportunity to change their operating practices to comply with Steam's rules.

However, the CSGOBig letter appears to go further than Johnson's statement, stating that any commercial use of a Steam subscription is forbidden. This new wording appears to close the gap on any form of CS:GO betting that uses Steam accounts to trade skins. However, it does not affect real-money gambling that does not involve the Steam ecosystem, which may be why sites like Unikrn were not affected.

theScore esports has reached out to Valve for comment and will update this story as details arise.

Jeff Fraser is a supervising editor for theScore esports.