I hired a developer and they now claim they have a copyright on the code, how did this happen?

In this day of a new app being developed every day, how does the company owner or management know who owns the code developed and when they could lose control over it?

Most issues of ownership for software code fall into areas of copyright (a form of intellectual property or IP), since they are usually "written works of authorship" and primarily covered by US copyright law.  Copyright protection provides the author with protection from reproduction by others.  There are times when works can be reproduced without violating a copyright under things such as the "fair-use doctrine," such as when sample pages from a book are reprinted in a blog with commentary by the blog author about their thoughts or criticisms about what is being said in the book.  The rights for copyright protection are generally given to the original author of the work for long periods of time (anywhere from 70 years to over 120 years depending upon all the facts).  After that amount of time has passed, the work is considered in the public domain and others can copy it without worrying about infringement. 

Insider Trading Crackdown on Congress- STOCK Act | H.R. 1148 S.1871

The Stop Trading on Congressional Knowledge Act (STOCK) has now passed both the U.S. House and Senate and should be signed into law by the president very soon. (Actual Text | Bill Summary & Status) H.R. 1148 or Senate Version S.1871 is the bill that seeks to impose heavier restrictions on insider trading that is done by or is connected to members of congress, federal employees, or employees of congress. Insider trading is covered by the Securities Act of 1934 and other related federal legislation and rules by the SEC and CFTC. It occurs when someone uses inside information as a basis to trade in stocks, commodities, or other types of securities. Inside information is defined as material non-public information. An example would be someone who works for a public company, gains information about something about to happen with that company that has not been disclosed to the public (e.g. significantly increased profits, new products about to be launched, etc.), and trades based upon that information.

"I didn't realize an email or downloading an app could be an enforceable contract"

With the ever changing technology and world in which we live, practices of how things are done change over time. This includes things like entering into contracts or modifying those agreements. Many people try to rely on the "I didn't sign anything" or "I didn't know" defense to get out of a contract, especially in the online or electronic context. These defenses may sound valid, but often people are not able to use them when it comes to things like email or online services. Several laws were put into place on the federal level and adopted by some of the states that address concerns about online transactions or agreements. The Electronic Signatures in Global and National Commerce Act (E-sign) and Uniform Electronic Transactions Act (UETA), and Uniform Computer Information Transactions Act (UCITA)(few states adopted this one) are all examples of such laws. These laws seek to make electronic communication or transmission of information relevant in the modern world to create things like enforceable contracts. They also put protections in place for consumers to avoid consumers being taken advantage of by things like hiding terms or conditions of use or making it clear that someone is being obligated by clicking on the "I accept" box or button. As just a few examples, courts have found that emails back and forth can be considered a signed written contract or that emails amended a contract, even though the physically signed agreement said amendments must be in writing. So your physical signature of your name is not required to obligate you. Also, when you click on that "I accept" button or even just by downloading a piece of software, you could be obligating yourself to certain contract provisions that may restrict or limit what you can do with their online service or software. The biggest thing that courts will usually look to is whether the party had notice of what they were agreeing to and whether they intended to agree. The intent to agree can sometimes be inferred by the fact that someone downloaded the software or took some other affirmative step, even if they later claim they didn't intend to be obligated. So just because you didn't physically sign a written contract, be aware that the next time you download an app or send off various emails, you may be agreeing to be bound by contract provisions which you may not have even bothered to read. Also, just because you aren't being charged for a service, your use of the software or other online service may obligate you to follow their terms and conditions of use.