* Q1 net profit 1.3 bln Sfr vs 919 mln Reuters poll avg
* CET1 ratio 14.1 pct in Q1 vs 13.8 pct at end-2016
* Says macroeconomic uncertainty, geopolitical risks remain (Adds detail)
By Brenna Hughes Neghaiwi and Joshua Franklin
ZURICH, April 28 (Reuters) - Swiss bank UBS kicked off 2017 with its second-best start to a year since the financial crisis as a brighter outlook and a spike in trading levels boosted its investment bank and core wealth management business.
Switzerland's biggest bank and the world's largest wealth manager said on Friday net profit for the first three months of 2017 rose 79 percent to 1.3 billion Swiss francs ($1.3 billion), overshooting even the most optimistic estimate in a Reuters poll.
"While the global recovery is likely to continue, macroeconomic uncertainty, geopolitical tensions and divisive politics pose risks that may affect client sentiment and transaction volumes," UBS said in a statement.
Net new money, an important indicator for future revenue in private banking, came in at 18.6 billion francs at UBS Wealth Management and $1.9 billion at Wealth Management Americas.
Rising interest rates, a booming stock market and improved investor sentiment boosted the group's U.S. business, while improving Asian markets saw clients in Asia Pacific begin taking more risks after a slowdown in late 2015 blunted trading appetite.
UBS had said it hoped optimism surrounding new U.S. President Donald Trump's proposed policies would boost its core wealth management business.
That optimism -- communicated just seven days after Trump took office in January -- paid off in the first quarter, as Wealth Management Americas saw a 10 percent rise in transaction-based income.
At its wealth management unit outside North America -- traditionally more profitable but facing greater pressure from negative and low interest rates -- a rebound in trading generated record revenues and profit before tax in Asia Pacific.
The bank confirmed its target of cutting costs by 2.1 billion Swiss francs by the end of 2017 versus 2013, saying it had saved 1.7 billion francs by the end of the first quarter.
UBS's common equity Tier 1 (CET1) ratio, a closely watched measure of balance sheet strength which the bank uses as a benchmark for its dividend, rose to 14.1 percent from 13.8 percent at the end of 2016.
$1 = 0.9947 Swiss francs Reporting by Brenna Hughes Neghaiwi and Joshua Franklin; Editing by Michael Shields