With the S&P/ASX 200 Index (ASX: XJO) down a hefty 0.24% at the market close this Thursday, it might come as a surprise to hear that we've seen not one but two ASX exchange-traded funds (ETFs) hit new all-time highs.

Yet that's exactly what this session has brought us.

However, the two lucky ASX ETFs in question are not index funds that cover ASX stocks. Or even international shares. They are gold exchange-traded funds.

Although ETFs are best known for the easy access they provide to entire stock market indexes like the ASX 200, they are also a popular vehicle for investing in alternative assets. There are ETFs out there that cover government bonds, cash, real estate, and commodities like crude oil, silver, and gold.

In the latter case, this provides a convenient alternative for those investors who might wish to invest in gold bullion but don't want the hassle of keeping heavy gold bars locked up in a safe at home.

The two ASX ETFs that hit all-time highs today are the Global X Physical Gold ETF (ASX: GOLD) and Perth Mint Gold (ASX: PMGOLD).

In GOLD's case, this ETF closed 0.92% higher at $42.70 a unit today. That's after hitting a new record high of $39.53 this morning.

With PMGOLD, this fund was up 0.92% to $42.70 per unit at the close after hitting a new all-time high of $42.75 earlier in the trading day.

Why are these ASX gold ETFs at record highs today?

We don't have to look too far to see why these two ASX ETFs have bucked the market and pushed higher this Thursday. PMGOLD and GOLD are directly tied to the price of gold. Both funds represent an underlying investment in physically vaulted gold bullion.

As it happens, gold has had a runup in price over the past day or two. This morning, my Fool colleague James reported that the gold futures price was up 0.4% to US$2,675.6 an ounce following the release of weaker-than-expected jobs data in the United States.

Now, that's not enough to mint a new all-time high for gold. However, given that our two ASX gold ETFs are priced in Australian dollars, the picture is a little different. At the current (approximate) price of $4,297 an ounce in our local dollar, gold is pretty much as expensive as it has ever been for Australian investors.

As such, it's not too shocking to see this reality reflected in the prices of the Perth Mint Gold and Global X Physical Gold ETFs today.