The financial account records net changes in foreign asset holdings and liabilities. Capital inflows (purchases of domestic assets by foreigners) finance current account deficits and can accelerate investment. The mix of capital flows matters: foreign direct investment is stable, while portfolio flows can be volatile. Large capital inflows can appreciate the currency and create sustainability concerns if they suddenly reverse, as happened in many emerging markets during financial crises.
The balance of payments, from your prerequisite, is a comprehensive accounting of a country's international transactions. The current account records flows of goods, services, income, and transfers — the things traded. The financial account records changes in ownership of financial assets and liabilities — stocks, bonds, loans, bank deposits, direct investments, and central bank reserves. Because every international transaction involves both a real-side exchange and a financial-side payment, these two accounts are mechanically linked: a current account deficit means a financial account surplus of equal magnitude, and vice versa.
The connection becomes intuitive with a concrete example. If the United States imports $1 trillion more than it exports (current account deficit of $1 trillion), foreigners are accumulating $1 trillion more claims on the US than Americans are accumulating on them. Those claims — held as US Treasury bonds, corporate stocks, bank deposits, or direct investments — appear as a $1 trillion financial account surplus. From your loanable funds background, think of it this way: a country spending more than its income must be borrowing the difference from abroad. The financial account records who is lending and in what form.
The composition of capital flows matters as much as the total. Foreign direct investment (FDI) — a multinational building a factory, acquiring a firm, or establishing a subsidiary — is considered stable and long-term; you cannot easily withdraw a factory if sentiment turns. Portfolio investment — foreigners buying equities, bonds, or fund shares on secondary markets — is more liquid: it can be sold with a keystroke. Short-term debt flows — interbank loans, commercial paper, money market investments — can reverse almost overnight. During boom times, developing economies often attract large inflows chasing higher yields, as capital seeks the highest risk-adjusted return internationally. These inflows may finance productive investment and accelerate growth, but they can create a dangerous dependency on continued foreign appetite for domestic assets.
The risk is the sudden stop: if foreign investors simultaneously lose confidence in a country's fiscal trajectory, exchange rate, or growth prospects, they sell domestic assets en masse. This drains the financial account, removing a critical source of financing. The country faces a painful choice — allow the currency to depreciate sharply (foreign demand for domestic assets has fallen, so the price of those assets, including the currency, must fall) or draw down foreign exchange reserves to defend the peg. The reserve defense buys time but is finite. Emerging market crises — Mexico in 1994, East Asia in 1997–98, Russia in 1998, Argentina in 2001 — all followed this pattern: sustained capital inflows enabled current account deficits and currency appreciation; when the inflows reversed, currencies collapsed and recessions followed. Understanding the financial account is understanding how international capital markets simultaneously finance growth and transmit fragility.