SEC Expands Collateral Options for Broker-Dealers in Securities Lending Markets

The U.S. Securities and Exchange Commission has introduced a significant regulatory update that expands the types of collateral broker-dealers can use when borrowing securities from large institutional investors. Under the updated framework, firms can now pledge diversified baskets of large-cap U.S. equities — specifically those listed in the Russell 1000 and S&P 500 indices — as collateral, a departure from the previously narrow set of accepted instruments such as cash, U.S. Treasury bonds, and bank guarantees.

This new asset class, officially termed "Eligible Equity Collateral," includes diversified portfolios of long customer margin securities or proprietary broker-dealer holdings drawn from both major indices. Unleveraged ETFs tracking the Russell 1000 or S&P 500 are also permitted under the updated guidelines.

Participation is limited to "Qualified Institutional Securities Lenders," meaning eligible parties must either qualify as institutional buyers under Rule 144A of the Securities Act of 1933, hold at least $100 million in securities on a discretionary basis, or work through an agent bank managing $100 million or more in outstanding securities loans. Broker-dealers are required to over-collateralize by 1% for loans denominated in major currencies — including the euro, British pound, Swiss franc, Canadian dollar, and Japanese yen — and by 5% for all other currencies.

Additional safeguards include daily mark-to-market valuations, mandatory diversification and concentration standards agreed upon by both parties, and a five-business-day grace period if eligibility conditions change. All pledged collateral must be held at an approved bank or registered broker-dealer.

Alongside the order, the SEC issued a coordinated staff interpretive letter to both SIFMA and ISLA, signaling a broader effort to modernize securities lending infrastructure. The regulator cited the liquidity, market depth, and low volatility of Russell 1000 and S&P 500 components as the basis for their selection. The move is widely seen as a step toward improving capital efficiency and strengthening risk management practices across securities lending markets.