diff --git a/src/main/java/com/acquirex/service/CardAcquisitionService.java b/src/main/java/com/acquirex/service/CardAcquisitionService.java
new file mode 100644
index 0000000..0d8493f
--- /dev/null
+++ b/src/main/java/com/acquirex/service/CardAcquisitionService.java
@@ -0,0 +1,116 @@
+package com.acquirex.service;
+
+import com.acquirex.dto.AcquisitionDto.Request;
+import com.acquirex.dto.AcquisitionDto.Response;
+import com.acquirex.entity.CardAcquisition;
+import com.acquirex.entity.CardAcquisition.AcquisitionStatus;
+import com.acquirex.entity.CardAcquisition.CardAcquisitionRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.util.Random;
+
+@Service
+public class CardAcquisitionService {
+
+    private static final BigDecimal MAX_APPROVAL_AMOUNT = new BigDecimal("10000000");
+    private static final BigDecimal SUSPICIOUS_AMOUNT_THRESHOLD = new BigDecimal("5000000");
+
+    private final CardAcquisitionRepository repository;
+    private final Random approvalCodeGenerator = new Random();
+
+    public CardAcquisitionService(CardAcquisitionRepository repository) {
+        this.repository = repository;
+    }
+
+    @Transactional
+    public Response processAcquisition(Request request) {
+        CardAcquisition acquisition = createAcquisition(request);
+        CardAcquisition saved = repository.save(acquisition);
+
+        if (!validateCardNumber(request.getCardNumber())) {
+            return rejectAcquisition(saved, "유효하지 않은 카드번호입니다");
+        }
+
+        if (request.getAmount().compareTo(MAX_APPROVAL_AMOUNT) > 0) {
+            return rejectAcquisition(saved, "승인 한도를 초과했습니다");
+        }
+
+        if (isSuspiciousTransaction(request)) {
+            return rejectAcquisition(saved, "의심스러운 거래로 거부되었습니다");
+        }
+
+        return approveAcquisition(saved);
+    }
+
+    private CardAcquisition createAcquisition(Request request) {
+        CardAcquisition acquisition = new CardAcquisition();
+        acquisition.setCardNumber(maskCardNumber(request.getCardNumber()));
+        acquisition.setMerchantId(request.getMerchantId());
+        acquisition.setAmount(request.getAmount());
+        acquisition.setCurrency(request.getCurrency());
+        acquisition.setStatus(AcquisitionStatus.PENDING);
+        return acquisition;
+    }
+
+    private boolean validateCardNumber(String cardNumber) {
+        if (cardNumber == null || cardNumber.length() < 13) return false;
+        int sum = 0;
+        boolean alternate = false;
+        for (int i = cardNumber.length() - 1; i >= 0; i--) {
+            int digit = Character.getNumericValue(cardNumber.charAt(i));
+            if (alternate) {
+                digit *= 2;
+                if (digit > 9) digit -= 9;
+            }
+            sum += digit;
+            alternate = !alternate;
+        }
+        return sum % 10 == 0;
+    }
+
+    private boolean isSuspiciousTransaction(Request request) {
+        return request.getAmount().compareTo(SUSPICIOUS_AMOUNT_THRESHOLD) >= 0
+                && request.getCardNumber().startsWith("9999");
+    }
+
+    private String generateApprovalCode() {
+        return String.format("%06d", approvalCodeGenerator.nextInt(999999));
+    }
+
+    private String maskCardNumber(String cardNumber) {
+        if (cardNumber == null || cardNumber.length() < 8) return cardNumber;
+        return cardNumber.substring(0, 4) + "****" + cardNumber.substring(cardNumber.length() - 4);
+    }
+
+    private Response approveAcquisition(CardAcquisition acquisition) {
+        String approvalCode = generateApprovalCode();
+        acquisition.setStatus(AcquisitionStatus.APPROVED);
+        acquisition.setApprovalCode(approvalCode);
+        acquisition.setApprovalTime(LocalDateTime.now());
+        repository.save(acquisition);
+        return Response.success(acquisition.getId(), approvalCode, acquisition.getAmount(), acquisition.getCurrency());
+    }
+
+    private Response rejectAcquisition(CardAcquisition acquisition, String reason) {
+        acquisition.setStatus(AcquisitionStatus.REJECTED);
+        acquisition.setRejectReason(reason);
+        acquisition.setApprovalTime(LocalDateTime.now());
+        repository.save(acquisition);
+        return Response.rejected(acquisition.getId(), reason);
+    }
+
+    @Transactional(readOnly = true)
+    public CardAcquisition findById(Long id) {
+        return repository.findById(id)
+                .orElseThrow(() -> new IllegalArgumentException("매입 정보를 찾을 수 없습니다: " + id));
+    }
+
+    @Transactional(readOnly = true)
+    public CardAcquisition findByApprovalCode(String approvalCode) {
+        return repository.findByApprovalCode(approvalCode)
+                .orElseThrow(() -> new IllegalArgumentException("승인코드를 찾을 수 없습니다: " + approvalCode));
+    }
+}
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