The S&P 500 closed at a new all-time high on Friday.

Why it matters: Reaching a new high-water mark confirms that we are indeed in a full-on, horns-out, snorting bull market, at least according to the conventional definition long used on Wall Street.

By the numbers: The S&P 500 closed the day at 4839.81.

• That's nearly 1% higher than the previous record of 4796.56 reached on Jan. 3, 2022.

State of play: Technically speaking, the bull market officially began — and the bear market ended — with the market's recent low on Oct. 12, 2022.

• Back then, investors were despondent amid a broad upsurge in inflation, an ongoing series of interest rate increases from the Federal Reserve and widely held expectations that a recession would hit in 2023.

Yes, but: The S&P is up 35% since then, as those anxieties largely failed to materialize.

• Inflation slowed, corporate profits rebounded, the Fed paused interest rate hikes — and has even opened the door to cuts in in 2024 — and the recession never arrived.

What to watch: Whether the bullish sentiment can hold up without tangible proof that rate cuts are coming soon.

• It may take a bit of bad economic news to elicit such murmurings from the Fed. And we've been waiting for that for a while.