Solidity Real Estate — APAC Compliance Skill

Singapore — MAS Property Fund Guidelines & ABSD

// Singapore: foreign ownership strictly restricted under Residential Property Act
// Foreigners cannot buy: landed residential property (houses, bungalows, terraces)
// Foreigners can buy: HDB resale (with restrictions), condominiums, commercial

enum SGPropertyType {
    HDB_FLAT,               // Public housing — Singapore citizens/PRs only
    PRIVATE_CONDOMINIUM,    // Open to foreigners
    LANDED_RESIDENTIAL,     // Singapore citizens only (generally)
    COMMERCIAL,             // Open to all
    INDUSTRIAL              // Open to all
}

enum SGBuyerType { SINGAPORE_CITIZEN, SINGAPORE_PR, FOREIGNER, ENTITY }

// ABSD (Additional Buyer Stamp Duty) — 2023 rates
struct ABSDRates {
    // Singapore Citizens
    uint256 sc_firstProperty;       // 0%
    uint256 sc_secondProperty;      // 20%
    uint256 sc_thirdAndAbove;       // 30%
    // Singapore PRs
    uint256 pr_firstProperty;       // 5%
    uint256 pr_secondProperty;      // 30%
    uint256 pr_thirdAndAbove;       // 35%
    // Foreigners
    uint256 foreigner_any;          // 60%
    // Entities
    uint256 entity_any;             // 65%
}

function calculateABSD(
    SGBuyerType buyerType,
    uint256 existingPropertyCount,
    uint256 propertyValueSGD
) public pure returns (uint256 absdSGD) {
    uint256 rateBPS;
    if (buyerType == SGBuyerType.SINGAPORE_CITIZEN) {
        if (existingPropertyCount == 0) rateBPS = 0;
        else if (existingPropertyCount == 1) rateBPS = 2000;   // 20%
        else rateBPS = 3000;                                    // 30%
    } else if (buyerType == SGBuyerType.SINGAPORE_PR) {
        if (existingPropertyCount == 0) rateBPS = 500;         // 5%
        else if (existingPropertyCount == 1) rateBPS = 3000;   // 30%
        else rateBPS = 3500;                                    // 35%
    } else if (buyerType == SGBuyerType.FOREIGNER) {
        rateBPS = 6000;                                         // 60%
    } else {
        rateBPS = 6500;                                         // 65% entities
    }
    absdSGD = propertyValueSGD * rateBPS / 10_000;
}

// MAS Property Fund Guidelines: real estate funds must be MAS-approved
// Leverage limit: 60% LTV for property funds under MAS guidelines
uint256 constant MAS_PROPERTY_FUND_MAX_LTV = 6000; // 60% in basis points

modifier sgForeignOwnershipCheck(SGPropertyType propType, SGBuyerType buyerType) {
    if (propType == SGPropertyType.HDB_FLAT) {
        require(
            buyerType == SGBuyerType.SINGAPORE_CITIZEN || buyerType == SGBuyerType.SINGAPORE_PR,
            "RPA: HDB not available to foreigners"
        );
    }
    if (propType == SGPropertyType.LANDED_RESIDENTIAL) {
        require(buyerType == SGBuyerType.SINGAPORE_CITIZEN, "RPA: landed residential for SC only");
    }
    _;
}

Hong Kong — Stamp Duty & SFC REIT Code

// HK: no foreign ownership restriction on property
// BUT: stamp duty surcharges apply
// SFC REIT Code: governs listed real estate investment trusts on HKEX

// HK Stamp Duty 2024:
// BSD (Buyer's Stamp Duty): 15% for non-HKPR buyers
// AVD (Ad Valorem Duty): up to 4.25% of property value (Scale 1) or 8.5% (non-residential)
// SSD (Special Stamp Duty): on resale within 24 months (10-20%)

struct HKStampDutyRecord {
    uint256 propertyValueHKD;
    bool isBuyerHKPR;               // HK Permanent Resident
    bool isCompanyBuyer;
    uint256 holdingPeriodDays;      // For SSD calculation
    uint256 avdHKD;                 // Ad Valorem Duty
    uint256 bsdHKD;                 // Buyer's Stamp Duty (if non-HKPR)
    uint256 ssdHKD;                 // Special Stamp Duty (if resale within 24 months)
    bytes32 stampDutyReceiptRef;    // IRD receipt reference
}

uint256 constant HK_BSD_RATE = 1500; // 15% for non-HKPR buyers (basis points)

function calculateHKStampDuty(
    uint256 valueHKD,
    bool isHKPR,
    uint256 holdingDays
) public pure returns (uint256 avd, uint256 bsd, uint256 ssd) {
    // AVD (Scale 2 for first-time HKPR buyer, else Scale 1)
    // Simplified Scale 2 rates:
    if (valueHKD <= 3_000_000e18) avd = valueHKD * 100 / 10_000;      // 1%
    else if (valueHKD <= 4_500_000e18) avd = valueHKD * 150 / 10_000;  // 1.5%
    else avd = valueHKD * 425 / 10_000;                                  // 4.25% Scale 1

    bsd = isHKPR ? 0 : valueHKD * HK_BSD_RATE / 10_000;

    // SSD: sold within 6 months = 20%, 6-12 months = 15%, 12-24 months = 10%
    if (holdingDays < 180) ssd = valueHKD * 2000 / 10_000;
    else if (holdingDays < 365) ssd = valueHKD * 1500 / 10_000;
    else if (holdingDays < 730) ssd = valueHKD * 1000 / 10_000;
    else ssd = 0;
}

// SFC REIT Code: HK REITs must distribute ≥90% of distributable income
uint256 constant HKRFIT_DISTRIBUTION_REQUIREMENT_BPS = 9000;
// Leverage limit: 50% of gross asset value
uint256 constant HKREIT_MAX_LEVERAGE = 5000; // 50%

Japan — J-REIT & Real Estate Transaction Act

// Japan J-REIT: investment corporation structure (not company)
// FSA regulated; listed on TSE (Tokyo Stock Exchange)
// Building Lots and Buildings Transaction Business Act: licensed agents required

struct JapanPropertyRecord {
    bytes32 chibanNumber;           // Japan cadastral lot number (地番)
    bytes32 householdNumber;        // Building number (家屋番号) if building
    address licensedAgent;          // Must use MLIT-licensed takken agent
    bytes32 agentLicenceNo;         // Real estate agent licence number (宅建業免許)
    uint256 transactionValueJPY;
    bytes32 registryDocCID;         // IPFS CID of 登記簿謄本 (certified registry copy)
    bool isCondominium;             // マンション — strata title
    bool hasJikenRestriction;       // Urban planning zone restriction
    JapanLandZone landZone;
}

enum JapanLandZone {
    CATEGORY_1_EXCLUSIVE_RESIDENTIAL,  // 第一種低層住居専用地域
    CATEGORY_2_EXCLUSIVE_RESIDENTIAL,
    CATEGORY_1_RESIDENTIAL,
    CATEGORY_2_RESIDENTIAL,
    QUASI_RESIDENTIAL,
    NEIGHBORHOOD_COMMERCIAL,
    COMMERCIAL,
    QUASI_INDUSTRIAL,
    INDUSTRIAL,
    EXCLUSIVE_INDUSTRIAL
}

// J-REIT: must distribute ≥90% of distributable profit to maintain pass-through taxation
uint256 constant JREIT_DISTRIBUTION_REQUIREMENT_BPS = 9000;

// Japan: foreign buyers must report to BoJ if property value >¥100M
uint256 constant BOJ_REPORTING_THRESHOLD_JPY = 100_000_000e18;

modifier japanForeignBuyerCheck(address buyer, uint256 valueJPY) {
    if (investorRegistry.isForeignBuyer(buyer) && valueJPY >= BOJ_REPORTING_THRESHOLD_JPY) {
        require(
            bojReportingRegistry.hasReported(buyer, block.timestamp / 30 days),
            "Japan: BoJ foreign investment report required"
        );
    }
    _;
}

South Korea — Property Reporting & K-REIT

// Korea: Real Estate Transaction Reporting Act — all transactions must be reported to MOLIT
// Foreign buyers: Foreign Investment Promotion Act — additional reporting

struct KoreaPropertyRecord {
    bytes32 pnu;                    // Property Number Unit (고유번호) — 19 digits
    bytes32 jibunAddress;           // Land lot address (지번주소)
    bytes32 doroAddress;            // Road name address (도로명주소)
    bool isRegulatedZone;           // 규제지역 — speculative area, overheated area
    bool isAdjustedZone;            // 조정대상지역 — loan restrictions apply
    uint256 transactionValueKRW;
    uint256 reportingDeadlineDays;  // Must report within 30 days
    bytes32 irtReportRef;           // MOLIT reporting reference
    bool isForeignBuyer;
    bytes32 mofReportRef;           // Ministry of Finance report for foreign buyers
}

// Korea: mortgage LTV restrictions in regulated zones
// Regulated area: LTV 50% for first home, 40% for multi-home holders
uint256 constant KOREA_REGULATED_LTV_FIRST_HOME = 5000;  // 50%
uint256 constant KOREA_REGULATED_LTV_MULTI_HOME = 4000;  // 40%

// K-REIT: must distribute ≥90% of earnings; listed on Korea Exchange (KRX)
uint256 constant KREIT_DISTRIBUTION_REQUIREMENT_BPS = 9000;

// Korea: real estate transactions in regulated zones require actual residency proof
// (anti-speculation measure for Seoul metropolitan area)

Australia — FIRB & Property Crowdfunding

// Australia: Foreign Acquisitions and Takeovers Act 1975
// Foreign investors must seek FIRB approval for residential property
// Temporary residents: can buy one established dwelling (must sell on departure)
// Foreign non-residents: cannot buy established dwellings (new dwellings only)

enum AUBuyerStatus {
    AUSTRALIAN_CITIZEN,
    PERMANENT_RESIDENT,
    TEMPORARY_RESIDENT,         // Can buy one established dwelling
    FOREIGN_NON_RESIDENT,       // New dwellings only
    FOREIGN_ENTITY
}

// FIRB thresholds 2024-25
uint256 constant FIRB_RESIDENTIAL_THRESHOLD_AUD = 0;        // All residential requires approval for non-PR
uint256 constant FIRB_COMMERCIAL_THRESHOLD_AUD = 330_000_000e18; // A$330M for commercial (non-sensitive)
uint256 constant FIRB_AGRICULTURAL_THRESHOLD_AUD = 65_000_000e18; // A$65M for agricultural

struct AUFIRBRecord {
    bytes32 firbApplicationRef;
    AUBuyerStatus buyerStatus;
    bool approvalGranted;
    uint256 approvalDate;
    uint256 approvalExpiry;
    bytes32[] conditions;           // Any conditions attached to approval
    bool isNewDwelling;             // Foreign non-residents: new only
}

modifier firbCheck(AUBuyerStatus buyerStatus, bool isNewDwelling, uint256 valueAUD) {
    if (buyerStatus == AUBuyerStatus.FOREIGN_NON_RESIDENT) {
        require(isNewDwelling, "FIRB: foreign non-residents can only buy new dwellings");
        require(firbRegistry.hasApproval(msg.sender), "FIRB: approval required");
    }
    if (buyerStatus == AUBuyerStatus.TEMPORARY_RESIDENT) {
        require(
            !temporaryResidentHoldings[msg.sender],
            "FIRB: temporary residents limited to one established dwelling"
        );
    }
    _;
}

// Australian property crowdfunding: managed investment scheme (MIS) if pooled
// Requires AFSL (Australian Financial Services Licence) if MIS
// ASIC RG 176: property syndicate disclosure obligations
uint256 constant AU_MIS_INVESTOR_THRESHOLD = 20; // >20 investors = must register as MIS

Cross-APAC Common Patterns

// Distribution requirements by jurisdiction REIT type
mapping(bytes32 => uint256) public reitDistributionRequirements;
// SG S-REIT: 90% | HK REIT: 90% | J-REIT: 90% | K-REIT: 90% | AU AREIT: 100% (trust distribution)

// Foreign ownership percentage tracking (critical in all APAC markets)
mapping(uint256 => mapping(bytes2 => uint256)) public foreignOwnershipPct; // propertyId → jurisdiction → pct
// SG: track for RPA compliance | KR: track for regulated zone rules | AU: FIRB tracking

// Withholding tax on property disposals (varies by jurisdiction)
// SG: 15% for non-residents | HK: 0% | JP: 10.21% | KR: 10-20% | AU: 12.5% FRCGW
mapping(bytes2 => uint256) public withholdingTaxBPS; // jurisdiction → rate

Security & Compliance Checklist

• Identify target APAC jurisdiction(s) before implementing ownership/transfer logic
• Singapore: SGBuyerType enforced; ABSD calculated and verified; CSSD + HDB restrictions
• Singapore: MAS property fund guidelines — leverage ≤60% LTV
• Hong Kong: BSD (15%) applied to non-HKPR buyers; SSD on short-term resale
• Japan: MLIT-licensed agent address required; BoJ report for foreign >¥100M
• South Korea: MOLIT reporting reference stored; LTV caps in regulated zones
• Australia: FIRB approval verified for all foreign buyers; new-dwelling-only restriction enforced
• Australia: MIS registration check if >20 pooled investors
• All REITs: ≥90% distribution requirement enforced
• Withholding tax rates applied correctly per jurisdiction for non-resident sellers

Reference Files

• references/sg-property-restrictions.md — Singapore RPA foreign ownership rules, EC eligibility, HDB rules
• references/firb-guidance.md — Australia FIRB application process, conditions, exemptions
• references/jreit-structure.md — Japan investment corporation structure, TSE listing requirements