June 12 (Reuters) - A look at the day ahead in U.S. and global markets from Dhara Ranasinghe. It's a big week for markets with interest rate decisions from the three major central banks coming one after another. And one take away from last week's surprise rate increases in Canada and Australia, is not to take anything for granted.

World shares were steady near last week's 13-month highs on Monday, with European shares a touch firmer and U.S. stock futures pointing to a positive open for Wall Street.

In short, investors are biding their time - with May U.S. inflation data on Tuesday, released as the U.S. Federal Reserve kicks off a two-day meeting, event risk is high.

The Fed is widely expected to "skip", note, not "pause" hiking rates in June when it concludes its meeting on Wednesday. The European Central Bank is tipped to deliver a quarter-point rate hike on Thursday, while on Friday the Bank of Japan is expected to maintain ultra-loose monetary policy.

The debate in market circles has shifted in recent months. First, most major central banks (not the BOJ of course) were expected to pause after a series of rate hikes and move to rate cuts later in the year. Now any rate-hike pause is suspected to be followed by further tightening (not easing) to contain sticky inflation.

Last week's rate decisions support this idea -- the Bank of Canada hiked rates last Wednesday to a 22-year high of 4.75%, having held rates steady since January. A day earlier, Australia's central bank raised rates by a quarter point to an 11-year high and warned of further tightening ahead.

Those surprise decisions suggest that the rate trajectory traders have mapped out and priced in one day can quickly be made redundant the next.

Citi strategists said the Fed could be faced with the lesson that central banks such as Canada's have learned – further tightening is still needed to bring inflation to 2%.

With the U.S. debt ceiling wrangling over, focus may also turn to Monday's bill auction with the U.S. Treasury expected to ramp up bill sales from here.

Analysts estimate that in the week ahead, the Treasury may raise close to $400 billion between bills and coupons after selling almost $330 billion of bills last week.

In Europe, UBS on Monday said it had completed its emergency takeover of embattled local rival Credit Suisse CSGN.S, creating a giant Swiss bank with a balance sheet of $1.6 trillion and greater muscle in wealth management.

Switzerland must now contend with a bank whose balance sheet is twice as big as its economy, while Sergio Ermotti, who was brought back in as CEO to oversee the mega merger, faces tough strategic decisions as UBS integrates its smaller rival against an uncertain economic backdrop.

Events to watch for later on Monday:

* Auctions: U.S. bills, 3-yr bonds.

* U.S. May Federal Budget

(Reporting by Dhara Ranasinghe, editing by Ed Osmond)