Controlled groups and the research credit: aggregation under Section 41(f)

Section 41 is an incremental credit, and increments can be manufactured by fragmentation: split research into a new subsidiary with no QRE history and its "growth" over a zero base would mint credits from nothing. Section 41(f) closes the door. All members of a controlled group — using the Section 1563 tests with a more-than-50% threshold — and all trades or businesses under common control are treated as a single taxpayer. One computation, one credit, then an allocation.

The single-taxpayer rule

For computation, member boundaries disappear: current-year QREs, prior-year QREs (for the ASC's three-year average), and gross receipts are aggregated across the group, including foreign members' relevant history. The more-than-50% threshold — lower than the 80% used elsewhere in Section 1563 — pulls in structures that consolidated-return rules would leave separate. Common-control rules extend the net past corporations to partnerships and proprietorships under Treas. Reg. §1.41-6 and the Section 52 principles it incorporates; the regulatory text is at eCFR Title 26, and the code at the official IRC.

The rule cuts both ways. It blocks the fragmentation play, but it also means intercompany research arrangements are ignored — a member paying a sister company to perform research does not create 65% contract research; the group sees only the performing member's own wages and supplies. And qualified-small-business tests for the payroll offset apply at the aggregated level: a startup majority-owned by a fund alongside revenue-generating siblings under common control can fail the $5 million gross-receipts screen on group numbers.

Allocation among members

Since 2011, the statute allocates the group credit to each member in proportion to the member's share of the group's QREs — a clean pro-rata rule replacing the older stand-alone-credit method.

Example — a three-member group with a $500,000 group credit:

Each member reports its allocated share on its own Form 6765 (the form's Section E asks the controlled-group question directly), and each member's ability to use the share depends on its own tax posture — a loss member's allocation simply carries forward under Section 39 on that member's account. Elections add coordination problems: the Section 280C reduced-credit election is made member by member on original returns, and inconsistent member filings are a recurring cleanup item.

Why acquisitions change base amounts

Section 41(f)(3) is the provision deal models forget. When a taxpayer acquires the major portion of a trade or business (or a separate unit of one), the acquirer must include the acquired business's QREs and gross receipts in its own history for base-amount purposes, with interim-year proration; the disposing taxpayer excludes them going forward.

The consequences are mechanical. A buyer with a $3 million three-year QRE average acquiring a target that historically ran $2 million of QREs computes future ASC bases on roughly a $5 million combined average — so the combined company's credit is incremental over the combined history, not the buyer's alone. Post-deal claims that keep computing on the buyer's stand-alone base overstate the credit, and the inherited-history rule likewise defeats the tactic of buying a research team and treating its spend as growth over zero. On the sell side, a carve-out sheds history and can increase the seller's go-forward credit. Diligence should always request the target's QRE history, not just its credit carryforwards — the carryforwards transfer subject to their own Section 383 limits, but the history transfers by operation of Section 41(f)(3) regardless.

For the computation each member's allocation feeds into, see how to calculate the credit; for the record-keeping the aggregated computation demands across entities, see the documentation playbook.