Warren Buffett has said, "Market timing is both impossible and stupid." Does anyone have any questions about where the legendary investor stands on this subject? I didn't think so.

I agree with Buffett for the most part, although, perhaps, some individuals could get lucky now and then with their attempts to time the market. That said, buying certain assets during some periods makes more sense than at others.

I believe we're in such a period -- and I have an opinion about which exchange-traded funds (ETFs) to buy. Here are two Vanguard ETFs to buy hand over fist before Sept. 18.

Getting real (estate)

First on the list alphabetically is the Vanguard Real Estate ETF (VNQ -2.62%). You can probably guess what this fund focuses on -- real estate. It attempts to track the performance of the MSCI U.S. Investable Market Real Estate 25/50 Index. The "25/50" in the index name, by the way, means that no more than 25% of the fund's assets can be invested in a single issuer and that the sum of all the assets with weights over 5% can't be greater than 50% of the index.

This Vanguard ETF owns 155 stocks with a median market cap of $31.9 billion. As you might expect, most of those stocks are real estate investment trusts (REITs). The fund's top stock holdings include Prologis, American Tower, Equinix, Welltower, and Simon Property Group. It also owns a sizable position in a mutual fund -- the Vanguard Real Estate II Index Fund.

Income investors often favor REITs. It's not surprising, therefore, that the Vanguard Real Estate ETF generates solid income, with a distribution yield of 3.32% as of Aug. 31, 2024 (the most recent yield Vanguard provides).

Vanguard is known for its low-cost funds. This ETF is no exception, with an annual expense ratio of 0.13%. The average annual expense ratio for similar funds is 1.07%.

Thinking small

Two Vanguard ETFs are neck-and-neck for the second spot on my list. The Vanguard Small-Cap ETF (VB -2.77%) and the Vanguard Small-Cap Value ETF (VBR -2.73%) share much in common. I don't think buying both of them is the best move because of their overlap, so I'll pick only one. My choice is the Vanguard Small-Cap Value ETF.

Both of these Vanguard ETFs focus on stocks with relatively small market caps. The main difference, though, is that the Vanguard Small-Cap Value ETF also emphasizes attractive valuations. The average price-to-earnings ratio for the fund's stocks is 15.6 compared to 19.2 for the Vanguard Small-Cap ETF.

The Vanguard Small-Cap Value ETF owns 848 stocks (compared to 1,402 owned by the Vanguard Small-Cap ETF). None of its holdings make up more than 0.68% of the total portfolio.

There is one minor downside to buying the Vanguard Small-Cap Value ETF instead of the Vanguard Small-Cap ETF. The former fund's annual expense ratio is 0.07%, while the latter's expense ratio is 0.05%. However, that difference isn't a problem in my view, considering the lower valuation for the Vanguard Small-Cap Value ETF.

Why buy these ETFs before Sept. 18?

Now to the important question: Why buy the Vanguard Real Estate ETF and the Vanguard Small-Cap Value ETF before Sept. 18? Part of the answer is that's the date when the Federal Reserve is likely to announce interest rate cuts.

The Federal Open Market Committee is scheduled to meet next on Sept. 17 and 18. Federal Reserve Chairman Jerome Powell said on Aug. 23, 2024, "The time has come for our policy to adjust." Recent jobs and inflation reports increase the likelihood of a Fed rate cut.

The rest of the answer is that the Vanguard Real Estate ETF and the Vanguard Small-Cap Value ETF should move higher if interest rates decline. REITs and small companies are especially sensitive to interest rates because they often must borrow to fund their growth. Lower interest rates translate to higher profitability.

Investors should be aware that these Vanguard ETFs could fall if the Fed doesn't cut rates this week. However, I think the odds of a rate cut are high. Even if the Fed fails to meet expectations, both the Vanguard Real Estate ETF and Vanguard Small-Cap Value ETF should be great funds to own over the long term.