Sept 3 (Reuters) - The following are the top stories on the New York Times business pages. Reuters has not verified these stories and does not vouch for their accuracy.

- Eurozone growth has improved since the central bank began its stimulus program, but there are new uncertainties in European and global economies. (http://nyti.ms/1JOLI8M)

- Petco (IPO-PTAS.N) has drawn takeover interest from private equity shops including Kohlberg Kravis Roberts & Company as it continues preparing for an initial public share offering, a person briefed on the matter said on Wednesday. (http://nyti.ms/1JOM6Em)

- Natalie Massenet, the founder of Net-a-Porter and the woman who persuaded high fashion that it had a home online, is leaving the British luxury e-commerce group she built, just five months after announcing a merger with its Italian archrival, Yoox.

- Puerto Rico has secured a first foothold in its struggles with a towering $72 billion mountain of debt. The island's electric power authority and a group of big investors agreed late Tuesday on terms for restructuring as much as $5.7 billion of bonds. (http://nyti.ms/1JONh6E)

- The board of the California State Teachers' Retirement System, known as Calstrs, is discussing whether it would be best to shift as much as $20 billion of its portfolio out of stocks and even out of some fixed-income positions, in favor of something new, a "risk mitigation strategy." (http://nyti.ms/1JONozd) (Compiled by Parikshit Mishra in Bengaluru)