RPT-IPO VIEW-First-day pops crucial but no long-term guarantee

* All seven U.S. IPOs in 2009 have had first-day pop

* Strong first-day rises will help reopen IPO market

* Discounts on secondaries unusually high (Repeating item that initially moved on Friday)

By Phil Wahba

NEW YORK, May 22 (Reuters) - Stock underwriters are pricing shares for initial public offerings at lower-than-usual levels in an effort to stoke investor interest, which may explain why these shares have performed so well in their first days of trading.

Online restaurant reservations system operator OpenTable Inc (OPEN.O: Quote, Profile, Research) saw its shares jump 59.5 percent on their first day Thursday in the biggest first-day jump by an IPO in the United States in 18 months, while language training software maker Rosetta Stone Inc (RST.N: Quote, Profile, Research) rose 40 percent in its April debut.

All seven of 2009's U.S. IPOs have gained on their first day of trading -- usually by double digits -- following the last three IPOs in 2008, which fell in their debuts.

Bankers say they typically try to price a deal so the stock jumps between 10 percent and 20 percent in its debut. Shares of DigitalGlobe Inc (DGI.N: Quote, Profile, Research), a satellite image maker, rose 13 percent on their first trading day last week.

"If a deal opens in the single digits, buyers are not too sure how much demand there is for the stock, but if it goes up 40 percent, sellers can ask if they left too much money on the table," said Dan Simkowitz, Morgan Stanley's managing director and chairman of global capital markets.