Wall Street tracks one number more closely than almost any other: how much more—or less—the largest publicly traded U.S. companies are earning compared with a year ago. It is a pulse check not only for the market but for the broader economy, and that pulse is currently racing.

As of Monday, the blended earnings growth rate for the S&P 500 in Q2 2026 stands at 51%, according to an analysis by John Butters, VP and senior earnings analyst at FactSet, shared with CFO Daily. The blended figure combines actual results from companies that have already reported with estimates for those that have not. Because the calculation is a work in progress—refreshed as each company reports—the final growth rate for the quarter can still move before earnings season closes. If the number holds, it would be the index’s highest earnings growth rate since Q2 2021, when it reached 91.6%.

However, two companies—Alphabet and Amazon—are responsible for most of the jump in that growth rate since June 30. Both reported actual GAAP earnings per share that far exceeded analyst estimates, and both received a major lift from unrealized gains on investments recognized as other income. Under U.S. accounting rules, changes in the value of many equity holdings flow through net income each quarter, so paper gains can materially swell reported EPS regardless of how the underlying business performed. Alphabet posted EPS of $9.11 against an estimate of $2.88, while Amazon reported $5.75 versus an estimate of $1.82.

Strip out those two companies, and the picture changes. The blended earnings growth rate for the S&P 500 falls from 51% to 32.6%, per Butters’s analysis. That kind of outsized sway is built into index-level earnings math: because the aggregate reflects dollar profits, the largest companies carry the most weight in the headline number.

Yet even without Alphabet and Amazon, 32.6% would still mark the index’s highest earnings growth rate since Q3 2021, when it hit 40.6%, he noted. Those 2021 readings were themselves flattered by base effects, with growth measured against pandemic-depressed 2020 profits. It would also represent the seventh consecutive quarter of double-digit earnings growth for the S&P 500—a streak that predates the AI infrastructure buildout dominating headlines this year.

The strength is not confined to a couple of tech giants. Overall, 10 of 11 sectors are reporting year-over-year earnings growth, with nine of those 10 sectors posting double-digit growth. Energy earnings are surging 146.3% year over year, heavily supported by firm fuel prices. Communication Services earnings are up 116.9% year over year, largely amplified by mark-to-market gains from AI infrastructure investments; that sector includes Alphabet. Health care is the lone detractor, reporting a year-over-year profit decline of around 6.5%.

Butters also outlined common themes in what executives are discussing on Q2 earnings calls. The term “tariff refund” has been cited on only 35 earnings calls to date among S&P 500 companies for Q2. By comparison, “AI” has been cited on 305 calls, “inflation” on 193 calls, and “tariff” on 162 earnings calls so far in Q2. Those tallies will continue to climb until every company has reported, leaving a running record of what corporate America chose to emphasize this quarter.

This article was written by Sheryl Estrada (Sheryl.Estrada@fortune.com) and originally featured on Fortune.com.