买方限制：仅售予持《市场经纪备案证书》企业（全国共2.1万家）；
协议条款：加入“永不用于支付结算代理”承诺.
--------
Strictly Compliant English Translation

Buyer Restriction: Exclusive sale to enterprises holding Market Brokerage Filing Certificates (Total 21,000 certified entities nationwide).

Agreement Clause: Incorporation of "Permanent Prohibition on Payment Settlement Agency Use" binding covenant.