As the race for a spot Bitcoin ETF in the US accelerates, transparency over holdings will become a key competitive edge according to industry executive Samson Mow.

Mow, CEO of Jan3, says that while no current ETF applicants disclose on-chain wallet addresses proving Bitcoin reserves, he expects "one or more funds" to provide this verification "in a bid to be viewed as the most transparent and reliable issuer."

He notes that technically unbacked ETFs should not happen given tight regulations. However, violation of rules is hypothetically possible. Still, address disclosure would confirm holdings amidst any skepticism.

Other experts like Valkyrie CEO Leah Wald say public records from ETF providers should already allow investors to verify Bitcoin assets similarly to equity ETFs. Though some cite security in refusing on-chain transparency like Grayscale.

As the SEC nears a spot Bitcoin ETF decision, expected around January 10th, analysts predict "brutal" fee competition between issuers. Mow believes address disclosure will become a vital dimension along with fees.

So while unbacked products face improbable regulatory hurdles, the ETF race incentivizes real Bitcoin proof-of-reserves as a baseline credibility measure according to Mow. On-chain transparency could increasingly emerge as a selling point.