Spot bitcoin ETFs are approaching their five-month anniversary. The ETFs, particularly the freshly launched ones, have had unprecedented levels of success, smashing records and commanding public attention. In particular, BlackRock’s IBIT has been the main focus, becoming a leader in inflows and volumes as it attracted investors by being attached to the world’s largest asset manager while boasting a competitive 0.25% fee.

But for some time, IBIT was not the largest spot bitcoin ETF by assets under management (AUM). Its main competition was Grayscale’s GBTC, which started with a huge leg up in terms of fund size relative to its competitors since it was a trust converted into a fund, unlike the other ETFs that were starting from scratch.

Grayscale was holding about 619,220 BTC when the spot ETFs started trading, worth over $28.5 billion at the time. Meanwhile, IBIT started with a seed amount of $10 million and has been using inflows to grow its AUM.

Unlike all the other funds, Grayscale primarily faced heavy outflows upon launch, as investors were finally granted a redemption mechanism that had eluded them before the conversion.

So, the general trend that has emerged is that GBTC's AUM has been on the decline while the other ETFs have been growing, allowing them to put pressure on GBTC’s initial market dominance. On May 29, IBIT took that top spot, dethroning Grayscale as the spot bitcoin ETF with the most assets.

The shift came amidst a strong period for the spot bitcoin ETFs overall, which have tracked net positive flows across the funds since May 13 as the crypto market has shown a bit of a rebound after dropping in the wake of the strong rally into March. Grayscale’s outflows have grown more tepid, allowing the inflows into the other funds to counterbalance them more often than not.

Many of the same issuers are tailoring their S-1s for spot Ethereum ETFs after their 19b-4s got the green light last month. Once again, Grayscale will start with a sizable pot of ETH worth about $11 billion at current prices.

A similar mechanic will likely play out in the ether space as the new competitors grow while early ETHE holders redeem. It’s also likely we will see BlackRock again be the issuer showing the most significant early-stage growth as long as its fees align with others.

We now have a benchmark for how long it took Grayscale to fall from the largest AUM on the bitcoin side, and now time will tell if it's longer or shorter on the ether side.

This is an excerpt from The Block's Data & Insights newsletter. Dig into the numbers making up the industry’s most thought-provoking trends.