U.S. stock indexes posted solid gains midday Friday, as the Republicans scrambled to make final adjustments to the tax-cut bill. Volume was running higher on both major exchanges.

[ibd-display-video id=3025730 width=50 float=left autostart=true] The small cap Russell 2000 led the way up with a 1.2% pop. The S&P 500, which struck a new high, and the Nasdaq advanced 0.8% and 0.9% respectively. Blue chips trailed the leaders as the Dow Jones industrial average rose 0.6%.

Volume in the stock market today is likely to be higher because of expirations. Friday is a quadruple witching day, which involves the expiration of stock index futures, stock index options, stock options and single stock futures.

Tax-Cut Bill

If the Republicans wrap up the tax-cut bill today, a vote could come early next week. This would give President Trump a chance to sign the bill into law before Christmas , the New York Times reported.

For the stock market, the tax-cut legislation could be a driver in 2018. JPMorgan's top strategist Marko Kolanovic said in a note that "The upcoming reduction of U.S. corporate tax rates may be one of the biggest positive catalysts for U.S. equities this cycle." Kolanovic is convinced that "little is priced into the market."

The big question now is sector rotation . There are several ways to scan for sectors rising and falling. A thorough check might involve looking at which sectors are providing the most new highs ; the industry group tables; sector rankings in IBD's stock tables ; and breakouts.

Blue chips were up, except for IBM ( IBM ) which fell 1% in strong volume. In the Dow Jones industrial average, leaders included drugmaker Pfizer ( PFE ), up 1.8%; insurer Travelers ( TRV ), up 1.8%; and money center JPMorgan Chase ( JPM ), up 1.5%.

Under Armour Gaps Up

In the S&P 500, apparel stock the class C shares of Under Armour ( UA ) gapped up 11% as it reclaimed its 50-day line. The stock is a laggard and remains 50% off its high. The Street expects earnings to decline 73% in 2017, but then rebound 63% in 2018.

Under Armour's pretax margin has narrowed in each of the past three years through 2016 - 11.2%, 11.1%, 9.8% and 8.1%. The apparel industry group, though, has risen from No. 93 six weeks ago to No. 26 among 197 stock groups.

Advancing issues in the IBD 50 led declining issues by a roughly 4-to-1 ratio. The Innovator IBD 50 Fund (FFTY), an exchange-traded fund that mirrors the IBD 50 , rose 0.7%. The fund broke out in August and is about 9% above the 30.23 buy point. The ETF has returned to the 50-day area where it has not yet been able to establish support.

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The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.

The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.