Subscription
To subscribe is buy a financial instrument in the primary market, freshly issued, direct from the dealer, rather than by looking in the classifieds and buying second hand. It is very rare to buy shares by subscription (only on an initial public offering). More common for debt securities which tend not to be so liquid and not to trade so often in the secondary market, and par for the course for open-ended investment funds (like AIFs and UCITS funds)