Guaranteeing a Thai property company's loan: what suretyship law actually exposes you to

Setting up a 49/51 Thai company to hold land, then having the company borrow to fund construction, sounds like it keeps a foreigner's personal liability contained to their shareholding. It often doesn't: Thai banks routinely require the foreign director or shareholder to sign a personal guarantee (suretyship, ค้ำประกัน) before lending to a young company with no track record and thin assets of its own. The same personal-guarantee question comes up with seller or developer financing on a leasehold villa build, already flagged in passing in mortgage default and foreclosure. CCC Sections 680–701 — reformed in 2015 specifically to rebalance a law that had heavily favoured creditors — set out exactly what signing one of these actually commits you to.

The core suretyship rules

• Section 680 — suretyship is a separate contract: a third person (the surety) binds themself to a creditor to perform an obligation if the debtor — the company, in a 49/51 structure — fails to. It only attaches to a valid underlying debt.
• Section 686 — the creditor must give the guarantor written notice within 60 days of the debtor's default. Miss that window, and the creditor loses the right to claim interest, damages and expenses that accrued after the 60th day — a real, if partial, limit on how much a slow-moving bank can add to a guarantor's bill.
• Section 700 — if the creditor grants the debtor more time to pay without the guarantor's consent, the guarantor is discharged from the guarantee entirely.
• Section 701 — a guarantor can tender payment to the creditor as soon as the debt falls due; if the creditor refuses to accept it, the guarantor is discharged.

The 2015 reform that changed the balance

Before amendments effective 11 February 2015 (Amendment Act No. 20 B.E. 2557) and refined again later the same year, Thai banks routinely drafted guarantees making the guarantor 'jointly liable' with the debtor — legally a co-debtor rather than a true secondary guarantor, which stripped away the guarantor's right to insist the creditor pursue the company's own assets first. Section 681/1 now voids any clause forcing an individual guarantor into joint-and-several liability; that restriction doesn't apply if a *corporate* guarantor knowingly consents to joint liability instead, so this individual-guarantor protection is exactly what matters to a foreign shareholder signing personally. Section 681 was also tightened to require a guarantee to clearly specify the underlying obligation, the guaranteed period and a maximum guaranteed amount — an open-ended, blank-cheque guarantee sits on much shakier ground than it did before 2015.

What this means signing for a 49/51 company, in practice

• Check whether the guarantee is joint-and-several or a true secondary suretyship. Since 2015 a bank cannot lawfully force an individual into joint liability by contract wording alone — if a draft guarantee still uses joint-liability language for a personal (not corporate) guarantor, that clause is a candidate for being void, but get it confirmed by a Thai lawyer rather than relying on the bank's own template.
• Confirm the guarantee states a maximum amount and a defined period. A guarantee covering 'all present and future obligations' of the company with no cap is exactly the open-ended exposure the 2015 reform was meant to discourage — negotiate a ceiling tied to the actual loan amount.
• Keep your contact details with the bank current. Section 686's 60-day notice clock only helps if the bank can actually reach you — a guarantor who's moved back overseas and never updated their address loses the practical benefit of the notice rule even though it remains legally in force.
• Watch for loan restructurings. If the company later renegotiates repayment terms with the bank, insist on being asked to consent — under Section 700, an extension granted behind your back can discharge your guarantee, but that's easier to prove if you can show you were never consulted.
• A guarantee doesn't disappear if the company's own security is foreclosed. Thailand's no-deficiency rule under Sections 728–733 protects a mortgagor from being chased for a shortfall after a foreclosure sale — but that protection covers the mortgage itself, not a personal guarantee layered on top, which the 2015 reform regulates on its own separate terms.

A personal guarantee is the point where the limited-liability promise of a 49/51 company structure quietly stops applying to the person who signed it. The 2015 reform gives an individual guarantor real, usable protections, but only if the guarantee is actually worded to reflect them — read it with the same care as the loan agreement itself, not as boilerplate attached to it.