How a C Corporation Buys Transferable Tax Credits: Step by Step

A C corporation with federal income tax to pay is the natural buyer for credits sold under §6418: it can usually use the credit against regular tax, subject to the general business credit limit. This is the process from first estimate to filed return.

Step 1: Estimate how much credit you can actually use

Purchased credits are general business credits under §38, so your capacity is capped each year by §38(c). In the common case where the tentative minimum tax is zero, that cap is roughly 75% of net regular tax plus $6,250. Credits you already earn (such as the research credit) use the same room. See how the §38(c) limit works. Unused amounts carry back and forward, but you should not size a purchase around the carryover.

Step 2: Identify an eligible credit and an unrelated seller

Only the credits listed in §6418(f)(1) are eligible, including the §48 and §48E investment credits, the §45 and §45Y production credits and the §45X advanced manufacturing credit. The IRS says the buyer must be unrelated to the seller and must pay only cash (IRS Transferability FAQ, Q4 and Q5). A transferee cannot sell the credit onward (§6418(e)(2)).

Step 3: Diligence the credit

You are stepping into the seller's shoes. If the IRS later determines the credit was excessive, you can owe the excess plus a 20% addition unless you show reasonable cause (§6418(g)(2)). Request the IRS registration number for each credit property, the credit calculation, placed-in-service evidence, any prevailing wage and apprenticeship documentation, and the seller's recapture and indemnity terms. Your CPA's checklist is in the due diligence guide.

Step 4: Sign the transfer agreement and pay cash

The contract fixes the credit amount, the price (usually quoted in cents per dollar of credit), payment timing, representations, indemnities and any insurance. The price you pay is not deductible to you and is not income to the seller (§6418(b)), and the discount is not gross income to you (§1.6418-2(f)(2)). Timing of the cash payment is regulated; have counsel confirm the window under §1.6418-2.

Step 5: Use it in your estimated tax calculation

The IRS says a transferee may take a credit it has purchased, or intends to purchase, into account when computing quarterly estimated payments, but remains liable for underpayment additions and cannot take it into account earlier than the seller could. Read estimated taxes and credit purchases.

Step 6: Report it on the return

Both buyer and seller attach a transfer election statement. The buyer takes the credit into account in its first taxable year ending with or after the seller's taxable year for which the credit was determined (§6418(d)), and reports it with the registration number on Form 3800. See the reporting guide.

Step 7: Book it correctly

Finance teams should settle the accounting policy before closing. See ASC 740 treatment of purchased credits.

Worked example

A calendar-year C corporation forecasts net regular tax of $4,000,000 and has no other credits. With TMT at zero, the §38(c) cap is 0.75 × $4,000,000 + $6,250 = $3,006,250. It signs for $3,000,000 of credit at 92 cents.

Item	Amount
Cash paid to seller ($3,000,000 × 0.92)	$2,760,000
Federal income tax reduced	$3,000,000
Difference	$240,000 (8.7% of cash paid)
Remaining federal tax payable	$1,000,000

These are illustrative numbers, not a quote, and they assume the credit is allowed as claimed. Costs for diligence, insurance and advisers reduce the net.

Mistakes to avoid

• Sizing to total tax instead of the §38(c) cap. Credit beyond your capacity only carries over.
• Skipping the registration number. The transfer election requires it on both returns.
• Buying from a related party or paying with something other than cash. Either breaks the transfer.
• Assuming the seller handles recapture. For investment credits the buyer carries its share (recapture).
• Ignoring the books. Auditors will ask about the accounting policy.

Educational information only, not tax, legal or accounting advice. Confirm facts with your CPA and counsel.