Technical Depth
Wonder if PILOT can get this right? The rules where the detail gets lost.
A handful of international-tax rules are where engagements quietly go wrong — experts disagree, seasoned practitioners slip, and general-purpose AI answers them confidently wrong.
Here are nine. For each: the trap, the rule, and the exact authority PILOT pins it to — we leave hallucination no room to breathe.
Every quotation & citation below is drawn from PILOT’s own knowledge base — §958(a)/(b), Form 8621, §6038/§6038A. Nothing here is generated from a general-purpose LLM’s memory.
IRC §318(a)(3)(C) §958(b) Downward attribution — a foreign parent can hand its US subsidiary a CFC Commonly misstated A US company that owns no foreign stock can't be a US Shareholder of a CFC — or have a Form 5471 obligation. Flip for the rule → ✦ IRC §318(a)(3)(C) §958(b) The rule If a foreign parent owns ≥50% by value of a US sub, the parent's other holdings attribute down to the sub — making it a US Shareholder of a foreign sibling it never invested in, and turning that sibling into a CFC. “If 50 percent or more in value of the stock in a corporation is owned, directly or indirectly, by or for any person, such corporation is considered as owning the stock owned, directly or indirectly, by or for such person.” IRC §318(a)(3)(C) Treas. Reg. §1.958-2(d)(1)(iii)
IRC §958(b)(2) The completion rule — more than 50% of the vote counts as 100% Commonly misstated Attribute proportionally: a 60%-voting parent is treated as owning 60%. Flip for the rule → ✦ IRC §958(b)(2) The rule For §318(a)(2) upward attribution, once an entity holds more than 50% of the voting power of a corporation, it is treated as owning all of that corporation's voting stock — not its actual percentage. “…if a partnership, estate, trust, or corporation owns, directly or indirectly, more than 50 percent of the total combined voting power of all classes of stock entitled to vote of a corporation, it shall be considered as owning all the stock entitled to vote.” IRC §958(b)(2) Treas. Reg. §1.958-2(c)(2)
IRC §318(a)(5)(C) §318(a)(5)(B) Anti-churning — what comes in one way can't go back out another Commonly misstated Once stock is constructively owned, it can be re-attributed freely to everyone connected. Flip for the rule → ✦ IRC §318(a)(5)(C) §318(a)(5)(B) The rule Stock attributed into an entity by downward attribution (§318(a)(3)) can't be re-attributed back out to a different owner via upward attribution (§318(a)(2)). Family attribution likewise can't be chained twice. “Stock constructively owned by a partnership, estate, trust, or corporation by reason of the application of paragraph (3) shall not be considered as owned by it for purposes of applying paragraph (2) in order to make another the constructive owner of such stock.” IRC §318(a)(5)(C) Treas. Reg. §1.958-2(f)(1)(iii)
IRC §958(b)(4) TCJA §14213 OBBBA §70353 §958(b)(4) is year-dependent — the rule turns off, then back on Commonly misstated “§958(b)(4) was repealed” — stated flatly, as if it were permanent. Flip for the rule → ✦ IRC §958(b)(4) TCJA §14213 OBBBA §70353 The rule It turns on the foreign corporation's tax year: in force pre-2018 → repealed for 2018–2025 (TCJA §14213) → restored for tax years beginning after 12/31/2025 (OBBBA §70353). PILOT applies the right regime per year — and for 2026+ flags the new §951B regime for Professional review instead of computing it. “Subparagraphs (A), (B), and (C) of section 318(a)(3) shall not be applied so as to consider a United States person as owning stock which is owned by a person who is not a United States person.” (in force pre-2018; repealed 2018–2025; restored TY2026+) IRC §958(b)(4) Pub. L. 115-97 §14213 Pub. L. 119-21 §70353
§958(a) vs §958(b) IRC §951(a)/§951A/§956 “US Shareholder” is not the same as an income inclusion Commonly misstated If downward attribution makes you a US Shareholder of a CFC, you have a Subpart F / GILTI inclusion. Flip for the rule → ✦ §958(a) vs §958(b) IRC §951(a)/§951A/§956 The rule Filing status (US Shareholder, CFC) is tested on §958(b) constructive ownership; the income inclusion is computed only on §958(a) direct & indirect ownership. A constructive-only US Shareholder can owe a Form 5471 but zero Subpart F / GILTI / §956 inclusion. “A United States shareholder's pro rata share of a CFC's subpart F income and the amount determined under section 956… continue to be determined based on direct and indirect ownership of the CFC under section 958(a), which does not take into account such downward attribution.” Notice 2018-13 §5.02 Treas. Reg. §1.951-1(b)
Treas. Reg. §1.958-1(d)(1)/(d)(2) §1373(a) A US partnership is transparent for the tax, an entity for the filing Commonly misstated Treat a domestic partnership or S-corp one consistent way for every CFC purpose. Flip for the rule → ✦ Treas. Reg. §1.958-1(d)(1)/(d)(2) §1373(a) The rule For the inclusion (§951 / §951A / §956(a)) it is aggregate — transparent; the income runs to the partners or shareholders. For status (§951(b) US-Shareholder, §957 CFC, §956(c)/(d), §1248) it is an entity — the partnership itself is the owner. Same entity, opposite treatment, by purpose. Aggregate for inclusion — a domestic partnership is not treated as owning the foreign corporation's stock within the meaning of §958(a); each partner is (extended to S-corps by §1373(a)). Entity for status — that aggregate treatment does not apply for §951(b), §957, §956(c)/(d), or §1248. Treas. Reg. §1.958-1(d)(1) §1.958-1(d)(2) §1373(a) T.D. 9960 (2022)
IRC §6038(e)(2) Treas. Reg. §1.6038-2(b) Control runs through the chain — not by your percentage Commonly misstated Form 5471 Category 4 “control” means you own more than 50% of the foreign corporation. Flip for the rule → ✦ IRC §6038(e)(2) Treas. Reg. §1.6038-2(b) The rule Control of an upper corporation that owns >50% (by vote or value) of a lower corporation is control of the lower one too — chained through corporate tiers, non-proportionately. Own 60% of an upper foreign corp that owns 70% of a lower one → you control the lower (a Cat 4 filer); own 40% → no chain. A partnership or trust link breaks the chain. Control of a corporation that owns more than 50 percent (by vote or value) of another corporation is treated as control of that other corporation, chained through successive corporate tiers. IRC §6038(e)(2) (2nd sentence) Treas. Reg. §1.6038-2(b)
IRC §1297(a) §1298(f) Treas. Reg. §1.1298-1 A PFIC needs Form 8621 — no matter how little you own Commonly misstated No CFC — or just a small stake in a foreign company — means nothing to file. Flip for the rule → ✦ IRC §1297(a) §1298(f) Treas. Reg. §1.1298-1 The rule PFIC status turns on the company's income and assets, not your ownership. A foreign corporation is a PFIC if ≥75% of its gross income is passive or ≥50% of its assets produce passive income — and a US person who owns any of it generally files Form 8621 annually under §1298(f), with no minimum ownership %. The only break is a small-dollar value de minimis ($25k / $50k joint), which PILOT asks as a yes/no — never computes. “A foreign corporation is a passive foreign investment company if 75 percent or more of its gross income is passive income, or at least 50 percent of its assets produce, or are held for the production of, passive income.” IRC §1297(a) §1298(f) Treas. Reg. §1.1298-1(b)/(c)(2)
IRC §6038A(c)(5) Treas. Reg. §1.6038A-1(e)(1) Form 5472 runs on its own modified §318 Commonly misstated Reuse the §958(b) attribution to test whether a US company is 25%-foreign-owned for Form 5472. Flip for the rule → ✦ IRC §6038A(c)(5) Treas. Reg. §1.6038A-1(e)(1) The rule §6038A has its own modified §318: the corporation-to-shareholder threshold drops to 10% by value, it carries a separate foreign-to-US downward block (distinct from §958(b)(4) — and always in force), plus a §267(c) overlay and an anti-bootstrap rule. Different inputs, different answer. Section 6038A applies §318 with modifications — substituting 10 percent for 50 percent in §318(a)(2)(C), and not applying §318(a)(3) so as to consider a United States person as owning stock owned by a person who is not a United States person. IRC §6038A(c)(5) Treas. Reg. §1.6038A-1(e)(1)