Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

Perhaps it's only fitting that on the final day of the year the broad-based S&P 500 (SNPINDEX:^GSPC) would move modestly higher on in low-volume trading to close at yet another all-time high.

The stage has certainly been set for a continuation of the rally in 2014, with the unemployment rate sitting at a five-year low, U.S. GDP growing by its fastest rate in years at 4.1% in the third quarter, and home prices heading higher by double-digits for the year. By all intents and purposes, it was nearly a statistically perfect year, and hopes are high from investors that the good times will continue well into the new year.

With a fairly steady dose of economic data expected later this week, including weekly initial jobless claims figures, the ISM Index, crude inventories, and U.S. auto sales, the S&P 500 took today's lull as its cue to scamper higher by 7.29 points (0.40%) to close at 1,848.36.

Leading the list of gainers on this final day of trading in 2013 was chemical and waste management services company Valhi (NYSE:VHI) which advanced by 15.4% after announcing the passing of its chairman of the board, Harold Simmons. I know that may all sound a bit morbid -- Simmons was the board chairman for titanium-dioxide manufacturer Kronos (NYSE:KRO) and component products supplier NL Industries as well -- but Simmons was also known as a hard-lined corporate takeover expert, and investors are viewing his passing as an opportunity to unlock shareholder value that may not have been there when he was alive. I'm not certain I would consider chasing Valhi (or Kronos and NL Industries) higher following the death of its chairman, but I'd certainly consider adding it to my watchlist to see if it enacts any friendlier shareholder incentives soon thereafter.

Tissue engineering company Organovo Holdings (NASDAQ:ONVO) ended the year exactly as it began -- by shooting 12.8% higher in spite of no company-specific news. Organovo has raised more than a few eyebrows this year with its long-term potential to bioengineer organs, as well as to possibly grow cancer samples that biopharmaceutical companies can use to more rapidly and effectively predict toxicity and efficacy in studies of experimental compounds. Of course, all eyes are on Organovo's liver assay test which is scheduled to be released late next year. If this test fails to quickly generate revenue and slow the company's cash burn, then we could see Organovo lose steam.

Finally, small-cap clinical-stage biopharmaceutical company Immunomedics (NASDAQ:IMMU) tacked on 10.3% after announcing that it had received two U.S. patents, one of which includes its antibody-drug conjugate, SN-38. ADCs attach a chemotherapy toxin onto an antibody in an attempt to deliver that toxin directly to a cancer cell, thus preventing as much healthy cell death as possible. This patent assures that Immunomedics' ADC platform remains proprietary and, assuming its two midstage clinical studies deliver positive results, it could set the company up for a myriad of partnership possibilities.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.