Ethereum foundation has been selling off the ETH stock on regular basis since last year. Also Vitalik has been moving some of his own ETH from the market and moving to Coinbase. Currently there are some of the market analyst companies keeping an eye on the movement of the funds from the Ethereum foundation and Vitalik. 

Recently the analyst firm confirmed the movement of the funds. And they have posted about the same in the Twitter. You can check in below tweet.

You can check the proof for this data here. As you can see current balance in the data page is : $715.195M

As per their data Ethereum foundation still holds the 312K ETH. Which is a lot higher stake and not bad to hold considering foundation should have a vote in the DAO and other matters for the development of the blockchain. Considering they are holding the assets of stablecoin and other pegged blockchain which are elastic in nature you can expect this to be used for the payment of the grants and other internal fundings. But apart from that regular selling of the assets kind of raise the alarm. 

What you as an investor should do? It's not a panic moment as of now. Its still the reasonable internal audit and the movement of the grant and the funding. So that is kind of a difficult for the investors who are doing everyday trade on Ethereum. But for those who are staked and also getting the rewards out of their stakes, nothing changes for their investment.