韓國的「全租房」（Jeonse，전세）制度，表面上是一種租賃安排，但其內在結構實際上高度金融化，並與房地產市場形成強烈的正回饋機制。在長期低利率與資產價格上漲的背景下，這種制度逐步演變為推升房價與累積金融風險的重要來源，其核心關鍵在於「無息資金」與「高槓桿操作」的結合。

首先，全租制度本質上創造一個龐大的民間資金池。租客需一次性支付相當於房價六至九成的押金，對房東而言，這筆資金等同於無息融資。房東不僅無需支付利息，還可自由運用這筆資金進行再投資，最典型的形式便是「Gap Investment」（以租養房）。在這種模式下，投資者只需準備極少自有資金，就能透過租客押金持續購置新房產，形成多層槓桿結構。當市場處於上升循環時，這種操作會放大購買力，使需求被人為擴張，進而推動房價持續脫離基本面。

其次，全租制度促使資金快速金融化，並加劇信貸擴張。隨著押金金額不斷攀升，多數租客無法以自有資金負擔，轉而向銀行申請「全租貸款」。這意味著大量金融機構資金並未流入生產性投資，而是進入房地產市場，進一步強化資產價格泡沫。同時，這些押金在會計上雖屬房東的負債，卻未被完整納入宏觀審慎監管體系，使整體經濟的實際槓桿程度被低估。一旦市場反轉，這些「隱性負債」便可能瞬間轉化為系統性風險。

再者，低利率環境對全租制度具有明顯的放大效果。在利率長期偏低時，房東難以從金融資產中獲得足夠收益，因而傾向提高全租押金以彌補機會成本；另一方面，低利率也降低了租客的借貸成本，使其更容易承擔高額押金。供需雙方在同一方向上推升押金水平，最終形成對房價的間接支撐，進一步鞏固資產上漲的預期與投機行為。

然而，這種結構在市場下行時會迅速轉為脆弱。當房價停止上漲甚至下跌時，「逆向全租」（Reverse Jeonse）現象便開始出現：新租客願意支付的押金低於前一任租客的金額，導致房東無法以新押金償還舊押金。若房東本身資金槓桿過高，便會出現流動性斷裂，進而引發違約、法拍甚至惡意詐騙等問題。當大量物件同時進入市場拋售或拍賣，價格將面臨進一步下跌壓力，形成典型的資產價格崩跌循環。

整體而言，全租制度透過「租客負債化—房東加槓桿—資產價格上升—再擴張槓桿」的循環機制，將房地產市場與金融體系深度綁定。當外部條件（如利率上升或房價反轉）出現變化時，這種高度依賴信心與流動性的結構便容易失衡。近期韓國家庭債務已達GDP的極高比例，也反映出這一制度長期累積的風險正逐步浮現，並對整體經濟穩定構成壓力。

South Korea’s Jeonse (전세) system, while nominally a rental arrangement, is in practice highly financialized and deeply intertwined with the housing market. Over time—especially under prolonged low interest rates and rising asset prices—it has evolved into a key driver of housing bubbles and systemic financial risk. At its core, the mechanism hinges on the combination of “interest-free capital” and high leverage.

To begin with, the Jeonse system effectively creates a large, informal pool of capital. Tenants are required to provide a lump-sum deposit amounting to roughly 60% to 90% of a property’s value. For landlords, this functions as an interest-free loan. Not only do they avoid borrowing costs, but they can also freely deploy this capital for further investment. The most common strategy is “gap investment,” in which investors use tenant deposits to finance additional property purchases. With minimal personal capital, landlords can accumulate multiple properties through layered leverage. During an upward market cycle, this significantly amplifies purchasing power, artificially inflates demand, and drives housing prices away from fundamental values.

Secondly, the Jeonse system accelerates financialization and expands credit. As deposit amounts rise, many tenants are unable to pay out of pocket and instead rely on bank loans specifically designed for Jeonse. This channels a substantial volume of financial capital into the real estate sector rather than productive areas of the economy, further inflating asset prices. At the same time, although these deposits are effectively liabilities for landlords, they are not fully captured within formal macroprudential oversight. As a result, the true level of leverage in the economy is underestimated. When market conditions deteriorate, these “hidden liabilities” can rapidly transform into systemic risks.

Moreover, a low interest rate environment significantly amplifies the effects of the Jeonse system. With reduced returns from traditional financial assets, landlords are incentivized to demand higher deposits to compensate for lost income opportunities. On the other side, low borrowing costs make it easier for tenants to take on larger loans, enabling them to afford higher deposits. This alignment of incentives pushes deposit levels upward and indirectly supports elevated housing prices, reinforcing speculative behavior and expectations of continued price appreciation.

However, this structure becomes highly fragile during market downturns. When housing prices stagnate or decline, a phenomenon known as “reverse Jeonse” emerges: new tenants are only willing to pay lower deposits than previous tenants, leaving landlords unable to return the original deposits. Highly leveraged landlords may then face liquidity crises, leading to defaults, forced auctions, or even fraudulent behavior. As more properties enter the market through distressed sales, downward pressure on prices intensifies, creating a classic negative feedback loop of asset deflation.

In essence, the Jeonse system creates a cycle of “tenant indebtedness → landlord leverage expansion → rising asset prices → further leverage expansion,” tightly coupling the housing market with the financial system. When external conditions shift—such as rising interest rates or falling housing prices—this liquidity- and confidence-dependent structure can quickly destabilize. The recent surge in South Korea’s household debt to extremely high levels relative to GDP underscores the growing financial risks embedded in this system and its potential threat to broader economic stability.