Tax Credit Purchase Rates by Company Size: Analysis of 1,400 Public Companies

Mid-sized companies ($50M–$1B in annual tax expense) show the highest tax credit purchase rates at 9–16%, while companies with ETRs of 15–30% are most active buyers. Growth is fastest among smaller taxpayers, who doubled their purchase rate year-over-year — proving the market extends well beyond large corporations.

Denis Cook

Director, Business Development & Research

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The second of five data-driven posts exploring how companies are participating in the transferable tax credit market.

A common question in the transferable tax credit market is whether it is dominated by the largest corporations, or whether mid-size companies are meaningfully participating. SEC filings give the answer: mid-sized public companies, in the $50M-$1B annual tax expense range, showed the highest purchase rates.

Reunion analyzed over 6,000 public filings across approximately 1,400 of the largest U.S. public companies to quantify buyer participation. ASU 2023-09, a new accounting standard in effect for fiscal years beginning after December 15, 2024, requires more granular tax disclosures by public companies and makes credit purchases easier to verify.

Which Financial Metric Is the Best Proxy for Tax Credit Purchasing?

Among the size metrics we tested – revenue, market capitalization, employee count, and tax expense – annual tax expense showed the strongest correlation with purchasing behavior. This makes intuitive sense: tax expense directly measures the liability that transferable credits offset.

Companies in the $50M-$1B annual tax expense range showed the highest purchase rates, while those with lower tax expenses participated less frequently. The decline above $1B likely reflects that very large corporations often have alternative tax reduction strategies, including complex deductions and cross-border planning. It may also reflect that purchases for some large buyers do not cross ASU 2023-09 reporting thresholds.

Tax Expense Band	Purchase Rate
Under $50M	5%
$50M - $200M	9%
$200M - $1B	16%
Over $1B	9%

However, [growth in purchasers is fastest among smaller companies - link to first post]. Companies with under $200M in annual tax expense doubled their purchase rate year-over-year (from 21 buyers to 42 buyers, in the ~1,000 for whom Reunion analyzed both 2024 and 2025 annual filings). Purchasing among larger taxpayers also grew, albeit at a 50% rate – from 26 to 39 buyers.

Do Companies with Higher Effective Tax Rates Buy More Credits?

When we examine purchasing by effective tax rate rather than absolute tax expense, a parallel pattern emerges:

Effective Tax Rate	Purchase Rate
5% - 10%	2%
10% - 15%	5%
15% - 20%	10%
20% - 25%	14%
25% - 30%	11%
30% - 35%	7%

The highest purchase rate (14%) occurs among companies whose effective tax rate (ETR) is in the 20-25% range. The purchase rate stays elevated on both sides of the range as well, with over 1 in 10 companies with ETR’s of 15%-30% purchasing tax credits. Companies already benefiting from low effective rates (under 10%) have weaker incentive to purchase credits.

Key Takeaway

The transferable tax credit market is not just a large-company phenomenon. It is showing broad adoption among companies with tax expenses above $50M annually, with the fastest growth in adoption happening among companies with <$200M in annual tax expenses. This profile describes hundreds of public companies, and many private ones as well.

For the next post that explores the impact of tax credit purchases on company effective tax rates, [click here.] For the full series, [start here.]

Reunion maintains a database of public companies that have disclosed transferable tax credit purchases, available to entities buying or selling credits, and provides exclusive access to the underlying SEC data to existing buy-side and sell-side clients of Reunion. Reach out to your Reunion contact for access.

Data Notes

Analysis Period: February-March 2026

Universe: ~1,400 largest U.S. public companies

Filings Reviewed: 10-K, 10-Q, 20-F, 40-F filed since January 1, 2025

Methodology:

Credit Classification: Many filings reference transferable credits without specifying type. These are classified as clean energy credits since transferability is generally tied to Section 6418.
Sample Composition: Of approximately 1,400 companies, roughly 1,000 had filed both 2024 and 2025 reports during the analysis window. The remainder had not yet filed 2025 reports or had 2024 filings published before data collection began.
Data Quality: An AI-assisted process was used to scan filings. All identified purchasing activity was then human-verified at the company level.

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